Was booting now its not AN7 mobo

Wonder if anyone out there can help me.

I just got an AN7 uguru motherboard. Plugged it in and had frequent lock
ups when just trying to install windows.

Strange problems when rebooting. First it detected the chip as an xp1500,
then it showed it as an xp2400 (but in the cpu selector it always showed a
2400)

So I cleared the CMOS with the power cable unplugged. No joy.
changed the memory - No joy
changed the cpu - no joy.

When I boot it, the machine powers up but nothing comes through the
graphics card. The post error unit shows 90. If I do a reset with the
button it stays at FF.

Is there anything that Im missing and not doing here as its been a while
since I last did a motherboard install.

thanks