Ok, I have checked out ncix.com. These are the parts I picked, tell me if they will be able to run Half-Life 2. If they don't, can you give me a few auggestions for parts that will allow me to run those games, that aren't too expensive.
Video Card - GEFORCE 6600 GT
Hard Drive - SEAGATE 80GB HARD DRIVE
CPU - INTEL PENTIUM 4 3.0 GHZ
RAM - SAMSUNG 512MB
PSU - SPARKLE 300W ATX POWER SUPPLY P4 READY 120MM SILENT FAN 18A 12V
Mother Board - INTEL D865PERL ATX P4 S478 865PE DUAL DDR AGP8X 5PCI SATA SOUND MOTHERBOARD
Also if there are any other parts that I have chosen that you would like to know just ask.