I have a hand me down emachine T2865 2.8XP amd CPU computer! It's only running at half speed if I clear cmos and start it with windows xp home. It will run fine with no errors. If I optimize Bios settings the cpu then runs at 2.0 mhz but then when windows trys to start it crashes and starts a restart loop! Anyone ever run in to something like this! Tried using Safe mode but all it does is reboots and starts loop again!
Sounds like the bios may not be storing the settings, maybe a double check or replacing the bios CMOS battery could be worthwhile.
What happens when you unhook the hard drive? You should still be able to access bios set up check the settings and then try a reboot, this will confirm if it's a bios problem.
If all was ok with the hard drive disconnected you should get something like 'Please insert the disc with your operating system on', 'No hard drive found' or 'Hard drive failure', it'll let you know it can't find the operating system one way or the other. Doing this will prove if the fault is a driver conflict or data corruption etc has no data is gonna get loaded into RAM.
I would advise disconnecting all USB devices when tracing this kind of problem.
Can't Optimize Bios settings! 
Linear Mode
