I have just had a strange thing happen today(twice!),and was wondering if anybody can offer an explanation? My PC is a home build,approx 4.5 years old,and was quite high spec at the time. My motherboard is an MSI 865PE Neo2,and my problem is concerning the bios. First of all,my PC switched its self off,and when i restarted it would not boot....so i checked the bios and found that all date,boot sequence,and IDE configuration had been lost. I have 3 hard disks - 2 SATA and 1 PATA,with my MBR on one of the SATA drives. The bios was only recognising my PATA drive,so this is obviously what was causing the boot failure. I left it for a while then went back to it......everything was still messed up,but this time the bios was recognising my SATA drives...so i reconfigured everything the way it was,saved and rebooted - excellent,everything was working perfectly. Then...a little while ago,my PC suddenly restarted its self and did not boot. I checked the bios and it was back to the original problem. I left it for approx 30 mins,and when booting to the bios,my SATA drives were there,so i was able to reset everythign once again,save and exit...and everything is working fine as i type this. I suspect it might happen again(but then again it might not),so im wondering what could be causing it? Things that come to mind are....CMOS battery,or some kind of overheating problem....but for the latter i dont think it would affect the bios. Can anybody shed some light on this please?