trace.log?

Have Windows XP running on one of the machines in our testlab. Now we have the fiollowing problem. When working on the PC, after some time, lets say 6 to 8 hours we get an message saying the C: is full.
Strange because thath one has about 4 GB freespace. Had a look. We found a file called trace.log in the foler c:\windows\system32\logfiles\wmi\. Windows Management Instrumenation. And now he tricky part, we dont know how to put it of!
Had a look in performance but nothing is running there. Nomonitoring or something like that. Did a regedit, cant find \logfiles\trace.log. Nothing.
In our case we will have to reinstall. But if this happens again? Can someone help?