How do i do fresh install of Win7?

Well you just insert your Win 7 DVD & restart the PC. At the BIOS page, press the suitable button to boot from DVD. At the install page, you then get the options for formatting, deleting/creating new partitions, etc.

Hi, forgot to mention i have Windows 7 on an external drive not on DVD.

Exactly what do you have on your external drive? A fully installed Win 7 OS? Or just the installation package?

Probably the installation pakage. Working for a uni we can download the OS to load onto our PC's, from microsoft.

Then it's probably a 'iso image' of the installation package.
You can burn that image to a DVD and use the DVD to do a clean install that will include the option of formatting the hard disk.

ImgBurn is a free utility that makes it easy to burn iso images. http://www.imgburn.com/

Hello Howieleem,

You will of course need the DVD or USB drive setup with Windows 7 install package. At that point setup your BIOS to boot to DVD or USB depends on the media setup.
The Windows 7 install process will then begin. All applications and documents stored in other locations will have to be reinstalled / transferred manually.
For more information on the Windows 7 Upgrade, please go here: http://bit.ly/3DvynK

For additional assistance with the migration of Windows XP to Windows 7, please go here: http://tinyurl.com/mhbep4

thanks again,
John M
Microsoft Windows Client Team

You won't need to change any BIOS settings. Just use the F8 key when you power on. Keep pressing the F8 key till you see the Boot Options menu on your screen and choose the CD option to do a 1-time boot from your CD/DVD drive.

http://www.youtube.com/watch?v=ZQGcjnnT2Dk

Watch part 2 also!

It depends on the computer... some access a boot menu with F8, while others will use F10 or F12.