A PC running Windows XP set up for a single user (administrator) on a home network sharing a cable internet connection. The user gave his windows log-on password to someone. They logged onto their computer and did something when the user was away (not malicious, just.. something[i/]). Is there a log file/activity log that the user can look into to see what the other person was doing on his computer?

Thanks.

The only thing I can think that's native to the OS that you could look at is the event viewer.

Right click "my computer" and go to manage, you'll it there.

If it's an application your speaking of look under the Application log in the event viewer, it's should have records if installs and what not.

Look under the system log as well to see if they might be something there.

As MillerSHO said,  it depends on what you did.  

Two things I always check:

1.  Event Logs.  Open Event viewer.... but you probably wont find much.

2.  Search the entire drive for all files, modified in the last week.  (or whatever time frame)  If you know the exact time window the user was on, you can also learn a lot about what was done by seeing what program files were modified.