It's possible your CD drive is on the way out. If your laptop can boot
from a USB CD drive, try it in that. You could try running scandisk.exe
from the DOS on the USB stick, but IIRC, the DOS version of scandisk
doesn't understand NTFS, while the Linux utilities do.
Alternatively, if it was telling you there's no OS on the hard drive
before you tried to re-install, the HD may have died, and the easy way
to check this is to boot from a Linux Live CD or The Ultimate Boot CD,
and use the Linux utilities to check the HD.
http://www.ultimatebootcd.com/
There's a version of UBCD which will fit on a USB stick, or you could
just download the ISO file and burn it onto a CD-R.
--
Tciao for Now!
John.