This is pretty much the same question you asked yesterday, so understand that my answer is pretty much the same, albeit more detailed. You have to create the files where your email addresses and bookmarks are stored. You do this by Exporting the information (do Google searches with your program and the word “export” to find instructions). You would then move these files onto your external hard drive. Once you have installed Vista on your primary hard drive, reconnect the external one, copy the files to the local hard drive, and Import them back into the program. Your last question regarding “finding the download for a program you bought online” means you will need to find the executable file you originally downloaded and save that to your portable hard drive. This is sometimes saved in a Downloads folder, although with Firefox they often save to the desktop. You will not be able to copy the installed program to Vista, you need to have the installable EXE file to transfer your program successfully (and there could be issues with an XP program running on Vista, likely not, but there could be). Edit: I noticed you wanted to access the content from your external hard drive. I would advise copying it instead of running it off of the portable hard drive. This is because if you unplug your hard drive, your Firefox may have problems loading. If you wanted to access your bookmarks no matter where you went, I would advise using Portable Firefox, which will install Firefox on your portable hard drive.