How to change windows vista home premium to windows 7 professional ?

Hi!

Since you already have the installation file with you, you can now choose to do either a "clean" install or an upgrade. The difference between the 2 is that clean install removes all data from your hard drive while upgrade lets you keep your documents, pictures, music and videos in a file called "windows.old"

Here is the tutorial for how to do a "correct" install of windows 7:

http://www.maximumpc.com/article/howtos/howto_install_windows_7_right_way

Here are some additional tips:

1. Clean install should only be preferred when you want your hard drive to be formatted. Please note that all data would be lost, however.

2. Upgrade is possible from win vista to 7. You can not upgrade xp to windows 7 even if you have sp3.

3. Be sure to change the boot order in your BIOS to CD/DVD drive first before installing.

4. Make sure to back up your data (pictures, videos, documents) on an external device if you plan to do a clean install. 

5. Update your windows 7 immediately after installing it, before you install additional software.

6. Feel free to ask, if you require further assistance.

Hope it helps.