You'll have problems trying to run the newer games with the spec you have altho' the original Half-Life should run ok. You should be able to buy a graphics card IF you have an AGP slot altho I think you can get them for PCI. I suspect you would need a card that runs on 3.3v as opposed to the modern 1.5v. The amount of memory you have will also be a factor. As it happens I've got a Radeon 64 which is about the vintage you'd be looking for. I don't use it as I've moved on. See what others have to say and if you're interested let me know.