new processor but can't boot into XP

Gigabyte EP45 UD3R
Windows XP sp 3

I was using a slightly overclocked e5200. Bought an e8600 DUO Core and plugged it into MB. Set BIOs settings to fail-safe (tried optimized as well). Did not change any other hardware. System worked last time I booted to e5200.

I cannot boot into XP sp3. It will go into safe mode just fine. I've tried using msconfig to turn some stuff off but no joy. Tried turning on bootlog option but it doesn't seem to be work in except for booting into safe mode.

Booting to windows gives several different results: normally get to logon screen but freezes afterward. Sometimes it past the "Windows" logo with the moving boxes underneath then it indicates loss of signal to monitor.

I've never had this issue in 15+ years of computers so I'm a bit lost.

Any ideas?

What happens after you put the old CPU back in. If it still can't boot in, maybe something else is the cause.

Did your drive default to AHCI mode this time around but was installed under IDE?

Put original CPU back in and it works. Odd thing was mouse froze at logon screen. I unplugged then plugged it back in. No problems since then. I'm going to try the newer CPU again and try the mouse plug/unplug with it.

Post back if it doesn't, working CPU change itself should not make a difference, if everything else is the same.

Late update:

I sent the original CPU, e8500, back to seller as bad.

I then purchased a q9400 processor. It had lots of trouble getting into BIOS. Eventually figured out the problem was memory.

With my original e5200, I was running 2x1mb OCZ Gold PC2-8800 and 2x1mb Gskill PC2-8500 sticks. Ran fine with no issues. Overclocked and everything was good.

With the q9400 installed, I cannot get into the BIOS with the OCZ installed anywhere on the MB. Even if the only sticks in the MB are the 2 OCZ, I cannot get into the BIOS. If I use just the 2 GSkill, it works fine. I'll move my issue over to the memory or motherboard area since it isn't OS related.

Thanks all who responded!!