I recently bought an AGP GeForce MX 4.2 because the OnBoard SiS 7200 didn't satisfy my graphical needs. After some trouble getting it in there without the pc speaker complaining, it's in , the fan runs and I can boot. However, Windows doesn't detect the new card and when booting, I can still see that the old OnBoard card steals RAM... There are two options regarding videocards in BIOS: A switch between "OnBoard AGP" and "PCI", and one that lets you deside wether or not you assign IRQ to PCI VGA. I tried all combinations of the above options: OnBoard card gets the upper hand in all 4 cases. What's the problem here? Not enough IRQ?
P.S. the card works fine on another PC which has no OnBoard card. Just removed the old card, slid in the GeForce and everything happened automaticly

Without having the make/model number of your board, it's hard to say what the problem may be. There may be a jumper on the board to disable onboard video, along with the BIOS settings. There should also be a setting to allocate how much RAM the onboard video uses. Look for that & see what your options are there. If we knew what board you have, someone with some experience with that board may be able to help...or maybe one of us can get the manual online & have a look.