So, my first problem was the BSOD:
the registry cannot load the hive file:registry file failure
After restarting, attempting to start in Safe mode, and looking through many, many help sites, I used the info from http://www.kellys-korner-xp.com/xp_sys32.htm and did this:
I started from my XP CD-Rom and went into Recovery Console. Then, I typed the following commands:
ren software software.bak
This seemed to solve my problem. The blue screen was gone and Windows started normally. Except that everything I had ever saved or downloaded to my computer was gone. Gone! Help! I don't know how to get it back, and I'm sure it's there somewhere because I didn't delete anything. Any ideas?