You say that the drive is showing up in the BIOS, which means that the system sees it fine. Any issues are going to be with Windows. I agree with trying a Ubuntu or Knoppix live CD to get the files off of the drive. Also, for the permission issue, I assume that the drive is no encrypted and that you are administrator of the computer. If so, you can force it to give you permission to use the files. Right click on the files or folders that that you want, go to properties, Security, open up the advanced menu, go to the owner tab, and set yourself as the owner. Play around in the security menu a bit.