Issue with new LCD and Sage v6, and recommended hardware specs

[rtwhbw]

I have just purchased a Samsung 37" LCD. I have removed my 19 inch monitor. I had to adjust my screen area setting to 13**x7** (not at my computer and can not remember the exact numbers). That was the max setting on the screen setting for my computer. Now my LCD displayed my computer like a monitor, but everything slowed down. I thought I would try the trial version of Sagev6 as I have Sagev2 (I am only recording SD now). Now sagev6 sometimes works sometime not. When it does, and I fast forward, it takes it 10-20 seconds to redraw the screen, while the sound is still going.

Would it be an issue with an older computer not able to process the display aspect required for that size LCD? I currently use an old Dell 2.6 ghz, P3, 512 mb, video card is what came with it.

I am looking to upgrade my computer and dedicate it only to TV and DVD playback. Would you all recommend what I should purchase to build my own. I have a couple friends who would help me build it, but I would like an expert opinion on what equipment to buy.

Thanks
Rusty

PS - I have always wondered what is the deal with some many people having their cats as their avatar?