Window Xp boots to 98! Help!

Ok on my brother's computer I wanted to try my geforce 6800 on his computer to see if I still encountered problems. But when I took out his MX440 card and put in my 6800 for some weird reason it wouldnt go all the way in the slot. Also since he had no more of the power cable thing the red,black,yellow cable with the white haed I unplugged one of them from 1 of the hard drives. But since I couldn't get my card in any farther and get it to boot I took it out and put bak in the mx440. Then when I reboot his computer it shows Windows 98. The only hard drive that has 98 was my old computer hard drive which is one of the 2 in the computer. Then when it boots it says "While initalizing device NDIS: Windows protection error. You need to restart your computer." when I do i get the same error. What do i do?

double check your work ... cause your missing something or you changed something..

make sure you have the right ard drive selected to boot first .. re-check cable connections

Thx it looks like in the BIOS it changed it to boot the other hard drive first.

no problem !!

it probably has such an OLD agp slot it is not compatible - i hope you did try to force it in.