Well, the computer would not load in anything other than safe mode without getting a BSOD. I ran memtest, scandisk, defragmenter, and Avira but was still unable to boot into normal mode.
I reformatted the hard drive and then re-installed Windows XP. It is working perfectly now (for a 6+ year old computer). I was never able to completely diagnose what was causing the BSOD and boot issues. I am guessing it was a combination of use and virus/ malware infestation.