Dell optiplex 745 powers on but does not boot up no image on the monitor.

Does the power button stay green when you turn it on or does it blink orange.. Dell optiplex usuallly have numbers on them that blink..try to post the number code..or just go to this site to find out what they mean..

http://phubner.eng.ua.edu/Files/Optiplex%20745/trouble.htm

Here my troubleshooting procedure :
with a new motherboard : verify if all mounting standoffs correspond with the holes in the mobo !!
Or test the mobo ouside the case, on a wooden  (non conductive) surface
clean the system from dust, then  test with the minimum setup - disconnect also all peripherals and network cables :
connect only  motherboard + cpu + 1 ram stick, video card, power supply
verify that the 4-pin or 8-pin CPU Aux power plug is connected
on boot, do you have a display?
if NO it is one of the connected, swap ram, Power supply, video card or monitor - leaving only motherboard and cpu
if Yes, add devices till the problem shows

you can also check the motherboard for bad capacitors as shown here :   www.badcaps.net

additional tests and things to try :
boot without ram, it should beep; (also, without video card)
try bios default settings,(if possible) or clear the bios by removing AC and bios battery
renew the CPU heatpaste

Thanks guys but there is no image on the monitor. The system lights at the back show 3 4 in green which means there might be a issue with the ram, but i replaced it with new ram still no luck :(

If you are getting the same error code with the new ram, try starting the computer using 1 module at a time in different slots.

did you follow my troubleshooting exactly ?  it will show the problem !

hi nobus its a optiplex 745 small factor cannot change the graphics card on it. i think theres an issue with the graphics card no display at all.

I doubt that the graphics card is the problem. You will not get any display if the system cannot access the memory and that is what the error code indicates. You should test for that problem as I suggested above.
If you are getting the same error code with the new ram, try starting the computer using 1 module at a time in different slots.

why can't you change the card?  always possible

ive tried changing the memory in each slot no luck
i got ram from a working pc still no luck :(

why can't you change the video card ??

nobus -- you can't do anything with the graphics card because he's working with a SFF (Small Form Factor) system. These generally do not have bus expansion slots (PCI, PCIe, AGP, et al) and utilize chipsets like the Intel i945 which integrate most all system functions.

OP -- the 3/4 error is still inticating RAM, which could either imply bad ram or a bad motherboard. Your ram may be just fine and fully compatible but the motherboard is simply not responding correctly. Also, attempt reset your CMOS settings. Thought Dell motherboards do not allow custom configurations, they still may have gotten haywire for whatever reason. IIRC, this is a DDR2/533 memory configuration and should run fine in single module mode. If you have another RUNNING system with DDR2/533, borrow a single stick and press your luck. If it still fails, you may very well have a failed motherboard. Your 'graphics' are not broken.

oh yea ? from this page, you have 1 PCI-ex and 2 PCI slots - so why can't he change it, or answer my question ?

I believe this is the layout of his MB. No expansion slots at all. I am guessing that blackm3 didn't answer because he didn't know how to explain it any other way.

Maybe get a PCI video card..to see if that works..

You need to check the power supply. Either with a PSU tester or another PSU. It doesn't have to fit, just plug in the 24 pin and the 4 pin connectors into the motherboard and turn it on. If it works then it's your PSU.

Hi there are some diagnostic lights on OPtiplex's they are usually either on the back of the motherboard or the possibly the front they flash as the machine boots up a guide to what they mean is here  http://support.dell.com/support/edocs/systems/Op745/en/UG_en/trouble.htm#wp1114558

it may help you diagnose the issue

Apologies just realise that I starter I had mentioned this

Hvaing said that even if a machine is out of warranty Dell will sometimes help you diagnose an issue , (in case they can sell you the parts)

Thanks people will have to call dell and see what they say.

Dell engineer came and changed the motherboard all working fine now :D

The motherboard was faulty.