I have two Dell Optiplex 755s and both of them have a problem of turning on every time they receive power, the thing is the auto-start feature is turned off in the bios menu. I happened a few months ago, there was a blackout during rain at night, when the power came back, both computers started on their own. Both display the message system battery is low. I have checked the bios setup and the information is messed up, nothing is at its place and the date automatically changes to 2008. One of them is working fine but the other restarts just as it reaches the windows loading screen. I just tried different working hard disks and found out there is no fault. So, I tried different working power cells and they are not the problem as well. I ran onboard diagnostics and only the hard drive fails the tests. Can anyone help me with this?
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Considering the age of these PC's the first thing to do is replace the CMOS Memory (BIOS) backup batteries. The CR2032 coin cell battery is located on the motherboard. With the PC powered off, open the case and remove the old battery. WAIT 10 MINUTES then reinstall a new battery. The 10 minutes will ensure a BIOS reset and may fix the jumbled BIOS.
With power failures anything is possible, from jumbled/corrupted BIOS, to power supply, motherboard, CPU, etc. Have to take it one step at a time. If its the motherboard, considering the age of this model its not cost effective to replace the motherboard. A more modern refurbished PC can be purchased under $200 US.
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These models will not boot if the cmos battery is bad.
Go to the store and get a new Duracell DL2032 battery.
Blood sugar machines use the same battery so they sell them in most all the grocery stores.
I tried that, that didn't work. Everything is still the same, I even tried it with a different cell too. I think I should just get a new motherboard. Thank you for your reply!
I think I should just get a new motherboard. Thank you for your reply!
At the current price levels for old MBs like this, you should really think about getting a new system. It would be faster, more stable, cooler & quieter running, and just better overall.
Dell Refurb is having a President's Day sale with 40% off any item, and some of the desktops look mighty fine next to the cost, time and effort in replacing the MB on an ancient system that won't be getting faster anytime soon:
The best value right now is on 4th-generation i5 processors.
"Both display the message system battery is low."
So unless you are using a good battery that says guaranteed until 2024 or later its not likely to work.
You can get a working unit that will last a long time very inexpensively.