Haven't played Homeword 2, but I have played Warcraft 3, and I think I see your problem.
Sorry to say, but the GeForceFX 5200 is a cheap card and with good reason. Its performance is absolutely horible. If you're cranking up the detail level and resolution in Warcraft 3, that will cause some serious lag. The 5200 just isn't powerful enough to process all that data quickly enough to avoid lag.
Try turning down the detail levels and resolution, and it should help your lag problem.
Your other problem could be any number of things. Overtaxed power supply, bug in the BIOS, faulty IDE controller on either the motherboard or one of the drives, improperly set jumpers, bad IDE cable, the list goes on. It's generally not one of those things that can be diagnosed without actually being there to test things.
my friend constructed my computer for me and it's 'specs' are AMD Athlon(tm) XP 2400+, 2.00 GHz, 512MB of RAM, 80 GB, Geforce FX 5200, K7N2 Delta Series: MS-6570 (v1.X) ATX Mainboard(Nvidia nForce 2 Chipset Based).
I have updated the drivers to the latest and reformatted my computer twice however, when i play games like Warcraft 3 and Homeworld 2, when the display is set to the highest, I experience a whole lot of lag. Is that anything thing i could do? How would i know if its a hardware compatibility problem?
Also, occasionally my computer 'hangs' or stops at the startup: (where it does it initial memory check)wehn it says 'Detecting IDE drives'