Cannot install Win98/ME

I just updated the BIOS on my Ami motherboard to support a WD 40gb hard drive. Now when I try to install 98, I get an error: ‘Setup has detected a corrupt Setup (.CAB) file and cannot continue.’ I have tried three different 98 cd’s and one Me cd. I have also tried fdisk and format several times. I have also tried copying the files to the hard drive and running Setup from there. One time, I think Trend Guard detected the presence of a virus, but I booted to a Norton cd, and it didn’t find anything. Could the virus be in the mbr? And if so, how do I clean it? Help!