Virtual Memory

[jmk]

I was wondering if anyone can help me. We just upgraded our sons computer, we bought him an ASUS Motherboard M3N78-Vm and a Amd athanlon A64 x2 5200+ and 1 G of memory. Now alot of his old games aren't working, they freeze or one of them said it can't run because it needs 3mb of virtual memory, oh we are also using the on board video card. Someone said to disable the cool n' quiet. What else can cause this, these are all older games that ran for years on all our other computers when we had win98 win2000 and winxp pro, which is what we are still running. Can anyone give me advise as to what else to do or try? Thanks