New
#11
Ok I think we might be getting somewhere now I know the BIOS is working ok. Now you say you have most of the important data backed up - just make sure that you have cos if you do a factory default it is going to be gone!
Be absolutely sure that you have your pictures and docs and anything else onto an external or whatever you put the data on. You can still recheck via the Ubuntu OS for anything you have left behind or missed.
Now if you want to do this and I am not saying it will 100% work as the drive itself might be past it's use by date but it is worth a try. I have done this a few times with my Toshiba's when I have had problems with them.
Just to be absolutely sure what brand / model machine is it?
We need to know this because some of the brands have different F keys for different models for example I have to push the 0 key when powering on a Toshiba but if it is a Sony you have I have already seen three different combos.