Yes that's for another Dell but this failure can be a sign the CPU has failed. Did you try F2 and then save the BIOS settings for a test?
XP sp3 dell 5100 desktop
been running ok for 5 years
2 months ago installed second hard drive, working ok
2 weeks ago installed dell flat screen monitor
when starting system up message comes on screen:
Alert! Incompatible Processor Detected.
Strike the F1 key to continue, F2 to run
the setup utility.
I press F1 and go on with no appently problems.
This one tip will help you sleep better tonight
A few seconds are all you need to get a better night's rest.