Memory usage limit

[martypastor]

Is there a program or even a registry key from windows that limits the usage of a program and spend more on the Virtual Memory?
Like for example, the highest that eats my memory is the Mcshield.exe or what is called is the McAfee Realtime scan, The RAM of my computer is 256MB and Mcshield takes it about 25% or more, with svchost.exe and explorer.exe, the available space now is about 65% or it is about ~70MB availabe but the system cache takes about 98MB only, sometimes th system cache eats up to ~101MB and the availabe RAM is 55MB but the good thing is that it works fast. but when i cleared the RAM using a RAM cleaner (if I'm correct) it slows down instead of running fast but after minutes it stabilizes.
But the question is that is there a program or even a registry key from windows that limits the usage of a program and spend more on the Virtual Memory?
Thanks
Take a look at the pic. on the attachment

[Chai]

Your system is already assigning as much program to use virtual memory. 512MB should be the minimum to run XP properly.

[martypastor]

Originally Posted by Chai

Your system is already assigning as much program to use virtual memory. 512MB should be the minimum to run XP properly.

and is there a way to configure this via windows?
Well if theres none, thanks for the answer.

[zy]

you need more ram, virtual memory uses your hard disk.

virtual memory = slower
RAM = faster