low on virtual memory

[bosoxfan]

I've been getting this message every few days lately on my desktop. It's a dell about 3 years old. I don't even know the spec of it. But it was cheap.

It's slow to open programs but am trying to get some more time out of it.

What does low virtual memory mean and is there a cheap way to fix it?

It's probably not enough info but any help would be great thanks.