All bioses are slightly different, but look for the word "integrated" (ie. Integrated peripherals) or something like that. In one of the submenus in the bios, you should see something like "integrated video" or "intel extreme graphics" or something like that. Make sure you switch it from On or Auto to disabled, and then make sure you've removed the monitor cable from the integrated video connector and plugged the monitor cable into the video card you've just installed (and of course, after that, you must install the video driver to get out of vga mode). If there is no option to disable the onboard video, it could be that it does so automatically once you install a card (I had an IBM machine that did that back in the 486 days), so if that's the case, just make sure you've switched the monitor cable from the original plug to the new video card's plug.
Post back if that doesn't help.
To be honest though, unless you're getting major stuttering in your Sonar interface when bringing up plugin windows and such, your onboard might be good enough anyways (assuming you don't want to play games or watch DVDs as well).
And be very careful not to change any bios settings that you aren't absolutely sure what they do ...if it doesn't say "video" or "graphics", leave it alone, or you might have a hard time getting your machine working properly again. If you do know your way around the bios, then forgive me for that statement. When I was starting out, I found it easy to mess up the bios and had to "reset to defaults" to get a working machine again.
Good luck!
Edit: And above all...don't be embarassed...we've all been there. The only dumb questions are the ones you don't ask! ;)
Edit again: And though it usually makes no difference, if you see an option to set intitial display (pci or agp), pick AGP...just in case.
One last edit: It seems others have had problems with that motherboard, and some suggest flashing the bios to the most recent (I hope you know what you're doing there....follow instructions on the motherboard manufacturers website carefuly). But before you do that, check to see if the video card you bought requires a power connection from a floppy drive power connector first...if it does, you may need to connect one of those small floppy power connectors to the end of the video card for it to work (most modern video cards require either a floppy or hard-drive power connector and won't work without it). If all else fails, you could try an old cheap PCI video card, or just use the onboard video. Good luck mate!
post edited by OldGeezer - 2008/05/22 00:04:51