Dell hardware

Heya. Let me first list my specs.

P4 2.4Ghz
2GB DDR SD-RAM
128MB ATI RADEON 9800 Pro
20GB Hard Drive

It seems to me that my computer doesnt perform as hardcore as it should. Sometimes I’ll get a little lag in games (Dark Age of Camelot) when I have 2 Gigs of RAM. I’m not a computer idiot. So its not going to be something stupid like a cluttered harddrive or spyware and such. I think its my motherboard because its a Dell Motherboard :d: and also its a Dell Hard drive. So do you guys think me putting in a new good Intel Motherboard and a 120GB 7200RPM HD will help? Thanks