[SOLVED] PC blackscreen - unless I reset CMOS battery, it then boots BIOS and I can access Windows once - then repeat


Mar 14, 2016
Hey everyone,

I just came back from vacation to find my PC (1-2 years old) to stop working. During the night I wake up to my PC booting itself over and over again every few seconds.
After removing RAM, GPU, resetting CMOS it still kept rebooting, so I decided to buy a new PSU (thinking the old one might be broken, had some issues with that before). After switching out the PSU's the rebooting stopped and the PC turned on 'normally'.

However whenever I would start it wouldn't give a signal to my monitor. Only if I would take of the power, remove the CMOS battery, put it back in and turn the power back on, the PC would boot with screen, forcing me to launch into the BIOS. I tried resetting the BIOS but this problem kept persisting. If I would save & exit the screen would turn black and nothing would happen. If I would restart the process described above I would be able to load the BIOS again. So being in the BIOS I decided to click and load the drive which has windows installed, doing so launches Windows normally, if I however shut off the PC I need to repeat to process again (or be presented with a black screen once again). I tried taking out my other SSD and HDD and boot with a single drive which also had no effect.

Any ideas as to what might be causing this problem?


Feb 15, 2014
Well I did completely disassembled dead home server few minutes ago, to notice finally that CMOS battery has 1.5Volts (instead of over 3V as it should). Standard CR2032 one..
Yes it boots normally again and again as I test it now - it was dead after each succesfull start that was possible only if CMOS RESET jumper was used.
Exactly as the topic says..

This ASROCK H87Pro4 has no cmos battery voltage displayed in Hardware Monitor screen.. Try it - measure voltage or just replace it.



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