I would try unplugging the hard disk and then try booting from the CD/DVD. Maybe a bad DVD drive?
Oh, and I'm pretty sure your linspire stuff won't work on this board. Linspire became defunct back in 2007 according to Wikipedia and the last version released has a 2.6.20 kernel. So there's a lot of hardware that won't be supported by 2.6.20.
So I guess I would try booting the latest version of Mint w/o a hard disk plugged in. If you can do that, then plug the hard drive back in and maybe there's some other BIOS setting that needs to be set. If you can't, then I'd jiggle the cables to the DVD drive and if that still doesn't work, try replacing the drive.