I have been considering doing this for a while now since my PC started acting weird a few months ago after a case dusting/cleanout (nothing too serious, but weird nonetheless). In my motherboard manual, it gives me two (seperate?) ways to clear CMOS: a) By shorting two pins on the motherboard (with diagram). b) Removing the battery. Will I need to do both or just one to clear CMOS? To clear CMOS by shorting the two pins, how exactly do I go about doing it? Do I just use a normal drive jumper to short the pins? I assume that I put the jumper on while the power is off, but do I then need to turn the power on? How will I know that CMOS is clear? There was a thread on this not too long ago that breifly looked at CMOS and it said that when you clear CMOS, you lose everything. What is meant by "everything"? Surely not the data on my HDD's? If I clear CMOS, is BIOS affected at all? Will I need to flash BIOS again after clearing CMOS? And finally, if I clear CMOS, would it be recommended that I remove any hardware such as PCI cards or HDD's before doing so? I will be reinstalling Windows anyway, but I'm hoping this will sort out any problems that might have risen in the past few months ie minor IRQ problems (see BSOD IRQ thread in general hardware forum for just one example). I'd be extremely greatful if anyone could help me out here. Cheers in advance!