Then install Win98Se or ME from a Genuine installation CD. Install the M/board drivers, check all you Drives are ok.
Install your Graphics driver then Audio, Then Modem. If you have been in BIOS make sure your settings are correct for VGA.
If you happen to be in the Man/Cheshire area I may be able to help more.
Does this M/board have a built in VGA chip or do you have a AGP Card/PCI Card ?. Make/Model/and AGP x. please.