XP crashed

so i was using my computer today, and i was having some problems with the internet. I thought maybe I downloaded something that caused it to have a problem. I was connected just fine, I could play my online games (WoW, City of Villains, etc.) just fine, but opening up any web browsers would tell me it could not connect or whatever like when you aren't connected to the internet. I had the same problem with any instant messaging services i tried to use, they couldn't connect to the proxy server or something (i'm not sure what that means, but it was annoying) wich is not the usual response when i'm not hooked up to the internet. So I did a system recovery or whatever when you pick a previous date and it load to how it was then, and then i ran a registry booster program. it fixed the problems I had, and since i had used the system recovery, it asked me to shutdown after i was done testing and installing whatever need be tested/installed. So I let it shutdown, then I turned it back on, my REAL problem presented itself. it started going, through the XP loading screen, then the desktop started to appear, and all of a sudden, the xp loading screen returned, only slightly modified. it then told me that it could not continue the setup because the registry could not be updated. then it showed me a system log, and it said Fatal Error, or something like that and told me that it couldn't start up because of the registry not being able to update.

i've searched, and not found any fixed to my problem, most crash fixes that i've found were done when you actually can use the computer, but i can't do that because it won't start up. I've tried the F8 thing, and nothing happened.

so i'm basically stuck, i've no idea how to fix this problem, and that computer was what i spent a good deal of my free time doing here in this dinky little appartment.

somebody, anybody, please help?