Originally, my laptop's harddrive crashed. I thought this was a good time to upgrade, so I bought a 500GB harddrive. I plug it in and install windows on it, but it wouldn't boot. With some googling, it appeared that the laptop's BIOS wasn't able to handle harddrives that big. Updating the BIOS was a little too complicated for me without windows, so I played around with partitioning the drive using an Ubuntu live CD. At one point I was able to install Ubuntu on to the drive and have it boot into it, but I was never able to get windows to work.
At some point, the BIOS started to refuse to recognize that there was a drive in the computer. So, I decided to try again and bought a cheap 40GB drive figuring that I might be able to get windows installed on it, and then update the BIOS and then switch back to the 500GB. But the BIOS won't recognize the 40GB either while the Ubuntu live CD still does.
In summary, BIOS says there isn't a harddrive while Ubuntu says there is.