Earlier this year I bought a 160Gb drive for use as a back-up. For some reason it was never recognised properly on first boot, I had to either go into the BIOS and get that to recognise it, or re-boot Windows to get the BIOS to recognise it. In August I bought a 80Gb drive to use instead, (I had back-up problems with the 160Gb due to it not been seen in DOS where the back-up software worked from, anyway...), suprise suprise that didn't recognise properly on boot either.
In September I started wearing reading glasses (cos everything was blurred

).
This weekend I bought some new back-up software which works within Windows, so no booting to DOS to back up. Ah! I thought, now I can use my 160Gb drive. Looked at the drive, now with my reading glasses on, and spotted immediately the jumper was in the wrong place

. Looked at the 80GB...yup, same there. Changed the jumper setting for the 160Gb drive and it was recognised perfectly...
The moral is: If your drive wont boot properly, get some ******* glasses!!!