My computer says I am low on virtual memory. How do I clean this up

I have avg installed, no viruses, used malwarbytes, no malware. Used a good registry cleaner(registry cleaner) all taken cared of, I did disk clean up, all good, I even tweaked with the virtual memory and its still slow. I even tried to install super anti spyware and i cant, I get some type of error. I even tried to do system restore, but the pc wont let me open it(turned of by group). Is it just that I need more ram? Because i tried to run disk defragment, but it never finished(maybe because Im using vista, and I dont have enough ram. A little help please? Best answer for 10 points.

Ever since I downloaded an upgrade of Norton 360 to my computer this morning, it has been sooooooo slow. I’ve deleted my temporary internet files, defragmented the computer, boosted my virtual memory, and nothing has helped. Can someone help me? Thanks in advance.

My computer is slow. My virtual memory always says its slow. I have a virus protector that i quarintine the bad stuff ever once and a while. I want to set it back to factory settings. Will that delete unneccessary stuff? and make it faster? Can i do this w/o deleting some program like word? and powerpoint? if not are there any tricks to making it faster!?