Originally Posted by AmD~pWnD~yOu
ps. its not always the hardware thats the problem.Try and run a computer repair software(Advance System Care) and/or spyware/virus scan.Also Defrag, cant stress this enough.
Except in this case, it most likely is. Great idea in general, but his dad is running Vista on 1GB of RAM. Of course it won't be fast. That's like asking XP to run with 64MB of RAM. It'll run, but good luck getting anything done.
In terms of RAM, the Crucial Vinman posted is inexpensive and is usually the same type that OEMs use in system builds. That set should take the PC to max supported memory and perform well.