Dell Optiplex 755 hardware problems

wolve rine
wolve rine used Ask the Experts™
Hey guys when i trun on my Dell 755 optiplex it show the dell mono and key board doesnt work i cant go into bios and then it shows the message..  No device found
                     Achi bios not installed..
So what should i do now...?
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JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018
Get a bootable CD (Ultimate Boot CD or Knoppix). Try to start with this.  Does this work?

Is there no BIOS except for that message.

If so, there is a hardware problem and you need to get the machine serviced.
Can you use a USB keyboard in the back? Different keyboard?
I'd try to solve the keyboard issue first and the rest may go away. If you can't get a keyboard working and can't get into BIOS that will be difficult.

John Hurst has a great suggestion.  Booting from another OS.  Between that and trying different USB ports and keyboards there isn't much else to do.  I've seen the front panel go bad on many of the 745/755 models, but usually the power won't come on in that case.
Most Valuable Expert 2015
Remove the CMOS battery and replace it with a new one.
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noxchoIT Product Manager
Top Expert 2009
First thing to try is a suggested by rindi - CMOS battery. If the error is really generated by BIOS as you say then the motherboard is not ok. Is the PC under the warranty yet?
Most Valuable Expert 2015
Very unlikely. This model is pretty old with core2duo CPU and probably came with Vista originally. I just got one 2nd hand recently for 11.-- Swiss Francs, and it works fine.
Quid, Me Anxius Sum?  Illegitimi non carborundum.
Disconnect hard disk and try a bootable CD such as the UBCD as suggested by John Hurst.

UBCD obtainable from (if you need help obtaining or creating then ask)

See if the UBCD will boot and report back.

I suspect you've got a bad hard disk from the message "No device found"

The message "AHCI BIOS not installed!" may be normal according to and that site suggests various fixes.  But again I suspect a bad hard disk.
dbrunton, I expect hard drive possibly as well. I also wonder is this a RAID situation or just a normal drive?
dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.

Don't know.  Could be either.
Top Expert 2013
wolverine - post a picture of the screen you get

here is how i handle unbootable systems :                  (Short-overview-of-how-to-troubleshoot-bad-hardware-when-a-pc-does-not-post)
dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.

Good variety of suggestions on way to solve this problem, including battery replacement, keyboard replacement, test with bootable CD, various fixes for BIOS error message, hard disk failure and general troubleshooting.

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