Your 'Virtual Memory' also known as the 'Page File'. Should be set to 1.5 (one and a half times) the size of the 'RAM'. So if you have 2GB RAM it should be set as 3GB.
You can also see what applications are using your RAM.
On the 'Desktop' Right click the 'Task Bar'
Select 'Task Manager'
Click the 'View'
Click 'Select Columns'
Click the box next to 'Virtual Memory Size' then click OK
Click the 'Processes' tab
The last column on the right will now be 'VM size' If you run your eye down that list you will see what programmes are using most of the 'VM'
When I'm using art software I know how much VM they use. So I close down those applications when working on art projects.