Fans turn on, no video display, no keyboard indication

I would have tried another video card to see if that works. No display on monitor is a sign of a defect video card. if you have a old video card, test this out first.

Good luck :)

Its not the card as before installing the new CPU everything was fine plus there are other issues that are out of the ordinary like theres no post beeps, as soon as the switch is turned on at the back of the PSU the PC switches on without prompting by pressing the power button. Fans spin etc & HDD but the keyboard LED doesn't light up When rebooting without the memory I get the beeps to say its missing. I tried a 7600GT & exactly the same thing happens.

how many beeps is it? is it 2 fast beeps? This may help solving the problem, please tell how many beeps you hear

take a look at this page, it explains the beep codes good :)

http://www.computerhope.com/beep.htm

Sounds like bad memory, possibly bad PS/2 or USB ports.  Try using a USB keyboard in a different slot.
The memory may not be fit for the mother board.

"Also when I switch the PSU on at the back the PC starts automatically, any idea why it could be doing this?"

This setting is in BIOS.  You can specify if you want your computer to boot back up after a power outage.

One long, 2 short repeatedly which from using that beep code link provided means its a video card issue which has really got me puzzled now, it only does this when I don't install the memory  which is why I originally presumed it was picking up there was no memory or am I misreading the beeps? When I install the memory again I don't get anything apart from the fans spinning, no post beeps. Like I said aswell everything was working perfectly until I tried upgrading the CPU, I cleaned the cpu & reapplied thermal paste but there's no change.

Ignore me I reckon it was three short beeps, It seemed like the 1st beep was slightly longer - see i'm not used to this happening to me, i've been blessed with good luck on previous system builds ;)

well, the issue that you dont get any signal to the monitor also sounds like a video card issue.

Have you tried taking out the video card and reinstalling it in the slot?


I reckon you have an Award Bios, and then there are only possible RAM and video card, since other failure should get a video signal (also though you should get a video signal with defect RAM, but i may be wrong :))

If the motherboard beeps to indicate the memory isn't installed is that a sign that the cpu is working? - Can someone answer this one please?
 
Also when I switch the PSU on at the back the PC starts automatically, any idea why it could be doing this? - The bios has never been setup to automatically start on powercuts, if the switch is on it wouldn't turn on until the power button was pressed?

Many BIOS menus have an option called Restore Power After AC Loss (or something similar.) It is usually under Power Management Options (or similar name, depending on your BIOS brand and version. In the event of a power failure, it is designed to automatically boot a PC., which is especially useful for servers or other systems performing business functions, where you always want the PC to come back on if the power gets interrupted.

Check that setting. If it is set for "Power On" then either change it to "Power Off." There is also usually a mode called "Last State" which will remember whether the PC was on or off and return it to that state.


About the motherboard beeps when memory isnt installed, i dont know if this makes the system know that the CPU is working. but i would think not, as it just gives you a sign on that the memory isnt installed. this would probably be a function that is tested before the testing of a defect cpu

I'm lost then, 1 minute I had a perfectly good working PC & the next it doesn't even boot. I've tried a different CPU, graphics card, memory, not got another PSU but it has been working fine for 8 months I really don't know what else I could have missed or tried.

If you were replacing, upgrading a CPU what steps would you take?

To replace a CPU i would recommend following these steps on this site

http://www.hardwaresecrets.com/article/427

It could also be the PSU, if you havent tested that, it could be too little juice in the old one, or just a defect one

You might also consider detaching all the IDE/Floppy cables from your motherboard to see what happens, as well as removing everything down to the bare essentials: 1 stick of ram, video card (or onboard video if you have it). One last thing to try would be to reset your bios via the jumpers for it on your motherboard. For that it's best to check the manual for your board. In any case it should be pretty obvious which jumpers on your board do this. Usually it's done like this:

- Turn off the power switch to your PSU
- Unplug the power cable to the PSU
- Remove the battery on your motherboard
- Change the jumper to clear your bios, and wait 30 seconds
- Do everything in the reverse order
- Startup your computer, go into the bios, load the Setup Default (either F5 or F6 within the bios), and then make the changes you need to

Thanks Leeds,

I'll give it another whirl when I get home from work, why is it with computers that it could be million & 1 things before you actually find a solution? There doesn't seem to be anything that I haven't covered except for PSU so maybe I've shorted that somehow, anyway thanks for help & watch this space.

Cheers

Paul

It was working fine and you replaced the cpu then had the trouble, or it stopped working and replacing the cpu was one step in diagnosing the problem?  You know the earlier bios's on that board had a compatability problem with core 2 processors so unless you know your bios is new enough you might be better off trouble shooting this with the old processor.  And I get dinged for suggesting this, but power supply testers are cheap (some say they are dangerous, but they come with directions and warnings).

It was working fine, I replaced the CPU taking necessary precautions & now I have the symptoms set out above so I then re-fitted the old CPU thinking the new one may be a DOA & it I get the same symptoms. The Bios is the latest one from Asus & the board is quad-core compatible but seeing as the original CPU is having the same symptoms I reckon that the bios update thingy can be eliminated from the possible solution list. Worst case scenerio is that I've Fried two CPU's but I find that hard to digest at the moment :)

Ok, going from leeds last comment I have done everything he suggested & I have the same problem. The PSU works & has been for a while it's 700W one too so its not weedy however I really can't see what else it could be so may be this is the issue so I'm gonna dig out an old known to be working PSU & let you know

How do I test if a CPU is defective?

You need to replace it with a cpu you know works, or you can let the dealer check the cpu for you.

symptoms - why would the 3 keyboards light flash up once then disappear the keyboard appears to be dead e.g. caps lock etc doesn't light up when pressed, PC it powers up on its own, video card fan is very loud so seems to be running at a lot of rpm but doesn't slow again like normal after post, HDD makes its normal sound like its thinking about something but there are no post beeps to suggest error or success, However if I remove memory it beeps but if I remove the the video it doesn't.

If the above doesn't seem familiar ignore it as I still need to eliminate the PSU from being the problem.

I would have tested the PSU first yes, as you have tried all other options (video card, cpu, ram?)

How far in the boot are you getting? i thought you only got a black screen and didnt startup at all, just stood there with no signal to monitor?

Are you getting to post screen? if so, what happends afterwards?

No I don't get anything apart from everything powering up with no video & no sign of posting. If there is no post at all does that mean my PC is well & truly knackered?

No, it means your video card or PSU is truly knackered :) or perhaps motherboard

But i would have tested another working PSU and see if it works, and if not another video card (but you had tried this?)

Borrowed a spare video card & PSU from a friend, the PSU is a 420W Thermaltake. Same problem occurs so that leaves either the motherboard or the CPU or may be I've missed something else but I can't think what. I'm still very suspicious over this powering itself on business still. I had never seen it as an option in the bios & we had powercuts not so long ago but it never powered itself back on again. It feels like I may of missed something so obvious but I can't think of what it could be?

I don't think this gives the right symptoms, but you eliminated stuck power button as a possibility when you tried the mobo outside of the case?

I'm liking the mobo as the culprit.

Ok guys, I've found the source of the problem & it turns out that there is some kind of grounding problem after all that messin about & frustration ;). CPU, memory, board, video card all work ok. Now I have the board out of the case there is obviously an issue with the grounding within the case. I have checked the stand offs & they seem fine, what other advise can you offer to resolve this issue or could it just be that the contacts around the screw holes are worn?

Ok, grounding problem occur becouse you dont use the "screw holes" that followes your mobo, there are some gold sticks that you need to place inside the screw hole in case BEFORE you screw in the mobo, if you dont do this the mobo will get connected through the entire case, which is not good.

The gold "screws holes" NEED to be screwed in case before placing the mobo inside the case, as the manual should say ;)

If you have done this, there is probably something wrong with the mobo :/

Along with that, cases might have more holes for stand-offs than the mobo has so make sure you only have stand-offs that match holes in the mobo.

The gold sticks you mention are the standoffs aren't they? I would never connect a motherboard direct to case as I know that would be disasterous so are you saying that if I've done that then there'd a problem with the motherboard even though it works outside of the case?

Is there a certain type of screw that is required, I usually use the small ones with the saucer like shape around the head but these don't screw in securely to the standoffs so I've used a slightly larger version without the thin saucer shape they do however cover the contacts?

I just grab some out of my box of miscellaneous screws.  I think as long as they thread smoothly, seat all the way, and the head doesn't extend beyond the little circle around the hole on the mobo, then you're fine.

I reckon my mobo has some kind of intermittemt fault then, its doing the same thing outside the case now.

That would be it then. I would have tried another working one :)

I haven't got another board that will support the oc2 memory I have or a quad-core cpu so it looks like i'm going to have to buy a another board.