Reinstalling Windows 7 W/anytime upgrade.

I am planning on a fresh install of W7 from my original Home Premium
full version disk that has been upgraded to Ultimate with Anytime
Upgrade so I need to know the procedure well before I begin. I need to
have the key available that will install Ultimate. I tried a repair
install in the past but that only got me to the original version and
would not accept the key I used using Belarc Advisor so I have to
restore my system with a cloned copy and was back at square one. Is
this something that can be done with a call to MS when I try to
activate or some other way? I have never gone through this process
with Win7 although I have done it with WinXP Pro several times.

I have several Windows Home Premium Disks here that I purchased for
other systems but I am not sure which disk goes with what computer.
Are there any differences and will I need to use the right disk when I
do a clean install on all the systems? I plan on doing this because I
want to have a fresh install on the SSDs I am now using to be sure I
have them all aligned properly.

If anyone can post a step by step procedure I would be very grateful.

Thanks.

Al.