OS Help!

I'm currently running Windows Vista Business (Terrible right!) and I w as planning on switching it from Vista to Windows 7. How do I do this? Do I completely erase the Hard Drive and then install Windows 7? Or is there some other way? Thanks for the help anyways. If it helps I'm installing the OS via USB.

Think with Windows Vista Business you can upgrade to 'Windows 7 Professional' or 'Windows 7 Ultimate' (NOT Windows 7 Home Premium) without having to do a total re install. 

How would I do that kind sir?

http://windows.microsoft.com/en-us/windows7/help/upgrading-from-windows-vista-to-windows-7#T1=tab01

What if I planned just to delete everything. I don't really have any important files on this computer so I though it would be better to just delete everything. Can I still do that and install the OS as if I just build the PC?

Yes, you just change your BIOS to boot to the CD and then it's intuitive from there on out.

But I'm not installing via DVD, instead I'm using a USB.

Then boot with the USB?