Don't know if this will help, but I had a similar prob a while back.
I was trying to install Linux and sometimes it wouldn't install, and sometimes it would, but then fail to boot and/or function correctly.
Eventually, aftar a lot of blind alleys (inc testing checksums on CDs), I tried replacing the drive with a new CD/DVD drive.
Voila, install perfect 1st time, system functions just fine ....
YMMV