Q: Where can I get antivirus software cheap/free?
A: Try
AVG Anti-Virus Free Edition.

Q: Is there anything special I need to do before removing a hard drive from an existing system?
A: Uh, how about turn off the power to that system first? But really, there isn't really anything else to know...

Q: Will a 256 MB video card outperform a 128 MB video card?
A: No. More memory onboard merely means the video card has more memory for textures, and have enough buffer for higher resolutions at higher color depth. It has nothing to do with video card's speed. Video card's speed is determined by its 3D engine implementation and clockspeed, NOT by amount of memory.

Q: Is there such a thing as "Universal Charge" for PDAs that uses batteries?
A: Try here

Q: What kind of hard drive cable should I get? I'm getting confused with IDE/EIDE/ATA designations.
A: All you really need to know is get 80-conductor ATA133 cable. Those are backward compatible.