Hello, need help w/ an older machine

My sister is having problems with her computer, and I'm trying to help her out, but I'm kinda stuck. She has an old Dell Dimension 4100 with a P3 (don't know the speed) with WinME, and an ATI Rage 128 Pro. Originally, she had what appearred to be a simple corrupted video driver (max of 640x480 res, 16-bit colors, etc.) so I went onto Dell's website and got an updated driver. Installed it, It fixed her resolution and color depth. But now, I can't install DirectX, and anything that needs hardware acceleration, when I try to open the exe for it, I get a an error message that says that it can't access DDRAW.DLL. Any help would be greatly appreciated.