Scorpiontico, I'll give you a quick explanation of virtual ram and that'll give you a better idea of what to do to optimize your system using it. What virtual ram is is essentially using your hard drive as extra ram. Your OS will look at what you currently have in ram and will store the information that has not been used much on the hard disk thereby freeing up more ram for other applications. In windows land you can find that area used by the OS in a file in the root of your OS hard drive called pagefile.sys.
So for example if you opened up a program and left it alone for a while while using other programs, the OS would copy the information from that program onto the hard drive because it isn't being used often, when you then tried to use that program later, it would have to go to the hard drive to copy it back into ram and that's where you see the performance difference.
Now, when deciding what to do with your virtual memory, you have to consider if you have enough ram to cover what you need to do. If you use an application like photoshop with many pictures open, those pictures are held in ram and you could run out of ram quickly, this would be when virtual ram could be nice (i use it for this purpose). If you just use a few basic applications open at a time, you can disable your virtual memory and will see better performance because all your apps will be in ram all the time.
Maybe that was more information than you needed, but I'm sure someone out there wondered what virtual memory and that huge file in their c drive were.