IIS Stops working after 2-3 days

I am working on a project using classic ASP. Every time I install
Windows and IIS, it works for 2-3 days and then starts having problems.
Specifically, things that have to do with the FileSystemObject stop
working.

I have tried Win2k, WinXP, the IISs that go with them, different
partitions (fresh install), turning Windows Update Off as well as doing
full updates, and cannot find a solution that works for more than 2 or
3 days.

Is it a worm? A virus? A windows update glitch?

It is driving me crazy. Are others having problems like this recently?

Thank you,
A.L.