Using WinXP?
Sounds like it is simply doing maintenance during an idle period. That is normal! WindowsXP is smart enough to do some simple defragmentation and optimization of your file system after you let your computer sit for a while. It will optimize for a minute or two.
If you want to manually kick off this maintenance, go to
start menu -> run... and type the entire line exactly as you see it here:
Rundll32.exe advapi32.dll,ProcessIdleTasks
If you did it correctly, it won't give any errors, and you'll hear your drive start to chug away for a little bit.
As for the network monitor.. you could try
NetMeter. Free and simple to use.
- rp