What could be the problem when the card worked fine when I got my system running with the new mobo (asrock k7vt2), but when I installed via 4in1 drivers, the card olny works as a pci-vga adapter at 640*480*16, if I try installing/usin nvidia detonator drivers, the system fails to boot.

Sometimes, after the 4 in 1 update you need to reinstall the video card drivers. The way I would recommend doing this is to download the latest drivers for your card from its manufacturer, not from NVidia, then right click on My Computer, go to properties, device manager, expand the + beside display adapters (which means graphics cards), click on the driver listed, go to properties (bottom left), find the driver tab, click update driver, select specify the location of the driver, click on display a list of drivers in a specific location, click next, click have disk, and point Windows to the new drivers for your card and let it update. Reboot and see how it is.