Problem with my pc memory

The virtual memory of my computer is fluctuating but the most of the times it looks like the used space of the memory is growing up without downloading any file or doing something else.
What happen?

the first thing in my mind is a virus, or probably your PC reg is to full.

Just reset all of your computer programs.Or run a virus scan..[-_-]

How high is it going up?

If it is within the range of 200~500 that is a natural range for Windows based computers to function under. But to alleviate this problem...

Go to run, and type "msconfig"

Then go to startup, and uncheck all the programs you don't want running in the background.

Then go to services, (check hide all microsoft services) and uncheck all the services you don't want running in the background.

Restart, and check your page file (virtual memory) usage.

If that doesn't work, run spyware/adware/virus scans and the problem should be fixed.

Thankx everyone, but I pass from windows vista to win 7, of course my pc was cleaned up the all the necessary programs has to be installed and if the problem was fixed it was because the virtual memory was not making fluctuations far big like in the pass but the fluctuation itself continues.
What happen then?