CCMiller,
I've never tried this in safe mode, but let's see if it works.
Boot into safe mode. Start >> Run >> type: msconfig >> go to the Startup tab >> click Disable All >> Reboot your system.
If it boots fine, great! You know your issue is the result of one or more of the programs in that startup list. From this point, I would enable one by one to figure out which one causes issues.
However, if the problem persists, it's most likely an operating system issue. In that case, and again I've never done this in safe mode: Insert your XP CD in the CD-ROM and boot into safe mode, Start >> Run >> type: sfc /scannow >> Reboot.
Let us know how it all turns out.
J_