My PC keeps restarting and freezing and even provides no screen at times. If I leave it long enough and come back I can boot up to Win XP but can't get more than 8 - 10 minutes before it reboots or freezes.

I had temporarily swapped CPU's because I had a problem with my other machine - I swapped back. On reading the mobo book I think this causes a reset of clock speeds and yes, I occasionally get something that says the clock speeds need setting. I've tried a variety but can't get it to work. I've reset defaults, chosen "Manual", 1533mhz or 1150 and tried to pick a multiplier - I still get the problem. I'm also wondering whether I have a virus (although doubt this as I keep AV sw up to date online).

Any ideas? Anyone help on what my settings should be and how I work these out. The PC gas an AMD 1800 chip in it. The paperwork says 266mhz after this.

Thanks in advance.

Try clearing the CMOS with the machine unplugged. Use auto for the settings. After clearing the CMOS you will need to restore some setings. Date, time, boot order, onboard hardware selection/ deselection, etc.

Did you re apply thermal paste to the cpu?

AMD, the Athlon Xp runs at 1530 MHZ, Before setting this Clock Speed, Clear the CMOS by removing the Jumper and CMOS Battery in the Motherboard, with the machine unplugged.

Yes, I did re apply thermal paste. In fact i'm wondering if there's a problem with this as I'd booted up a couple of times without (keeping an eye on CPU temperature which went up to around 63/64c).

Have since checked the clock speed and it seems the reurn to default of 1533 and a multiplier of 11.5 is correct. hmmm...