Starry Night and several fails to initialize OpenGL

Hi
I seem to have trouble running OpenGL. I have a reasonably good computer (ASUS A7N8X deluxe, Athlon 2800+, 1 GB ram, 120 gb HD, Gforce MX 440 agp 8x). It initialy seemed to be something wrong with the video board, so I changed it. The problem persisted. Several games wouldnt even run from start (such as Homeworld 2) and most of them added big instability to my winXP system, like the computer would reboot sudenly (log on restart referred to a minidump) in the middle of a game play (Soul Reaver, FIFA 2004, Halo). Eventually some GIS softwares (IDRISI for instance) would also cause windows to crash, specially when treating some bigger satellite images. As it happens, sometimes my motherboard would peep for overheating or voltage. As bobbob sugested to Rafael999, I thought it could be related to some bad memory sectors. But using Starry Night I realized that something is NOT working with OpenGL, as, when I choose to use it to render it fails to initalize on the software. Also, though I known nothing about these things, it seems that the NVIDIA driver has very few resources for OpenGL on my advanced settings. Can anyone give me a hand on this?