Does my PC need more RAM? **NEW INFO**?

You need to do some research on your motherboard on how to structure your RAM in the slots. A bios update will probably be required. If you have 2 slots for RAM buy an additional 2GB stick from like newegg.com. You should always try to match RAM when possible, not just amount of memory, but also the speed of the memory. If you have 4 slots, you might be able to structure your 1 GB with the 2 512 MB sticks, but I doubt you can do the 512s with the 2 GB.