Windows 7: Down grading to home premium from professional

Hi, since purchasing my laptop i have upgraded to windows 7 Professional from Home premium which came with it.
My question is how do i remove professional to get back to home premium (OEM)? i want to use the professional key for a new desktop i am building. My thoughts are a clean install (and i dont mind doing that) but are there any easier ways to do it?

Reinstall windows using the key on your COA.

thanks, where do i find the COA?

never mind i found the key (on bottom), but how do i install it,

The key required can be found using a program such as Belarc Advisor. Download and install it from the link below and give it a try.
Belarc Advisor - Free Personal PC Audit

belarc advisor only found the current key not the key for home premium.

And i dont have any installation cd's or anything because home premium came pre-installed

Spinksy, Can we assume that you made your recovery disks when you first received your laptop? If not then you might be able to talk toshiba into sending you a set of recovery disks. If you plead a sad story then they might do it for a real cheap price.

Other than that, Can we also assume that you installed your windows 7 pro version and activated it? If so then you might have to activate it by phone (if it is a full commercial version) as the activation over the internet most likely won't work. If it is a oem copy of windows 7 pro. That is supposed to be a one time activation and can not be moved to another machine.
Full box copies in most cases can be transfered to another machine as long as it is removed from the last machine.

Also, All the toshiba's that I have owned came with the product activation codes on the bottom of the laptop.

Rich

1: no i didnt make any recovery disk when bought didnt no about that
2: yes ive installed and activated professional over the internet, professional was not oem(i dont think) i obtained the installation file and key from my uni

and there is a product key on the bottom of my laptop for Windows 7 Home Premium OA

also i just found this from google
"Toshiba laptops from mid 2007 onwards dont have a recovery disc supplied with a purchase of a laptop. Instead, Toshiba has added a hidden partion on the hard drive which contains the same files on a recovery cd / dvd. "
so i assume i dont need a recovery disc to get to original state

Spinksy, normally the first thing to do is to make your recovery disks as toshiba usually nags the heck out of you with pop ups. But that aside. Are you sure that there is not a key combination that allows you to do a system recovery when initially booting. I have never done that as I always make the recovery disk.

from my toshiba doc file

To recover the original factory image using the utilities on your
computer’s internal storage drive:

1

2

powering on the computer.

Give it a shot..

Rich

If you clean-installed Windows 7 Professional chances are the Toshiba recovery partition has been wiped.

You could:

1. Borrow a set of recovery discs if you have a friend or work colleague that has a set.
2. Contact Tosbiba to see if they can send you a set - don't tell them you installed Windows 7 Pro, just mention that your recovery partition is corrupted.

To add, as you have installed a "different" OS (from the OEM supplied version) on the machine, the recovery partition may still be there but because a different OS has been installed the recovery partition may not work (reinstall). I've seen this happen on Dell's.