Explorer crashing inexplicably

No idea how to go about fixing this...

This handy little box will appear at certain points while I'm in Windows Explorer, most often when I try to open a specific folder within My Documents. Also, this problem seems to be interfering with Windows Live Messenger and Norton AntiVirus, causing both to crash. Probably other things that I haven't witnessed yet, too, as this isn't my normal computer. How my family manages to do these things, I don't know. I'm running Windows XP. What's wrong, and how can I fix it? Thank you!

 

there is a problem with the active sharing aspect of windows live messenger. it creates a file in C:\documents and setting\user\local settings\application data\messenger\emailaddress that causes explorer to crash when it tries to access the file, unfortunately i don't know why it crashes or how to fix it, but that's likely the problem you're running into. sorry i couldn't help more.

 

Well, thank you for the response, anyway. That's odd about the sharing... it doesn't seem to glitch out my own computer at home. Seems to be the cause, though, you're right. I'll keep playing with it.