Problem booting from wd0

I am trying to install 3.7 on a cheap PC. The system boots fine from the CD and installs without problems. However, when I try to reboot from disk, I only get: booting hd0a:/bsd: 4729760read text: Invalid argument failed(22). will try /obsd I am trying to use a recent snapshot; here is the dmesg

Re: Problem booting from wd0

Thanks for all the suggestions. It appears to be a problem with disk block mapping even though LBA mode is used. In light of the suggestions, this is what I did today: Use dd form /dev/zero to wipe MBR and start of disk. Check Bios settings - AMI Bios set to "Auto" shows LBA mode and DMA, etc. D