URGENT:Slow Access/Hangs

I have a PC in Network (PIII – 64MB RAM with WIN2K PRO)when the machine boots up the memory available shows 3K only, but the machine speed is OK, but after 4-5 hours of work it gets very slow and sometime hangs also. The user work on shared files throughout the day.

I have tried RAM cleaner etc but no much use. I checked out the virtaul memory was specified abt 1000 MB (10GB HDD) which was wrong and I changed it to 240-400MB range.

but still the prob exists…
thanx in advance