The installation process depends on if you have a retail/OEM or a preinstalled (customized) copy of Vista. If it's the latter it will automatically format your hard drive. If it's the former you will be presented with an option of which partition you wish to install Vista to, and just below that will be a Format button. Sometimes you must run DBAN, but in most cases the above is sufficient.
For the retail/OEM installation procedure:
1.) Insert the Vista DVD and reboot your computer.
2.) If necessary, adjust your BIOS boot order so that your optical drive is the primary boot option. (See entering system BIOS.)
3.) When prompted to press any key to boot from CD/DVD do so.
4.) Select your regional settings, enter your product key, and accept the licensing agreement.
5.) Choose a Custom installation.
6.) Choose the existing partition and click the Reformat button.
7.) Proceed through the installation wizard and account creation process.
For the Windows Easy Transfer wizard, you can follow these guidelines and instructions from Microsoft.
Finally, you shouldn't have a problem using Firefox in these forums, although the alignment may look slightly different. What viewing problems are you encountering?