How to legitimise Win7 license

Hi,
I have been asked to help a lady who has been defrauded with her system. She originally had a Vista based Acer laptop, which was upgraded by a 'friend' to Windows 7 (for which she was charged). It turns out that the Win7 version is an Enterprise edition and she doesn't have a licence key, any paperwork or software CD!
I would like to help her legitimise the Win7 licence but I am unsure if she should purchase an upgrade version or a full retail product. As this is in the UK the full retail version is very expensive and we would like to use an upgrade version if at all possible. Obviously, we would also like to avoid doing a clean installation if possible, but would appreciate views on which version to purchase. Finally, as the system currently runs the Enterprise version, can we replace this with a Home Premium version without doing a clean installation?

PCWorld £129.95.
MICROSOFT Windows 7 Home Premium Deals | Pcworld

Novatech £74.99.
Microsoft Windows 7 Home Premium 32-bit DVD - OEM - Service Pack 1 | GFC-02021

You will need to do a clean install.
Clean Install Windows 7

A clean reinstall may not be required... There is a tutorial on the Windows 8 forums that shows how to install Win8pro over Win8Media edition, which may work...

Media Center - Remove and Go Back to Windows 8 Pro

I don't know if it'll work for sure, but hypothetically you could change the registry values to match home premium, which would allow you to install professional or hp without losing anything.

If you feel you have no other options: try following the tutorial I linked to, but use this reference picture (click to zoom in):

jc836 said:

Unfortunately-the Wondows 7 Enterprise ve4rsion is exactly that. The License is tied to a large firm under contract with Microsoft. With that said-you would do well to obtain the OEM edition of Windows 7 Professional, which has the feature set included in Enterprise. Most people don't need Ultimate or its cost. I never install Home Premium for clients unless they absolutely insist (true it is cheaper).
Another thing-the only way to do this will be a clean install. This is according to Microsoft. The only direct path for upgrades is Home-Pro-Ultimate. Make sure you have a disc with all of the drivers from Acer before starting. Windows 7 is very good with them but the vendor ones are usually better. Also, keep in mind that a new copy of Windows 7 (any version0 should have SP-1 included. There will be a large group of updates to do after the machine is running.

Good luck

Hi,
Many thanks for the rapid response. I guess I'm not surprised about the clean installation, based on the stuff I have read elsewhere. However, I was surprised that you suggest that an OEM version would work. I was anticipating that using an OEM version would be rejected when the activation process occurred, as this system was built approx. 5 years ago with Vista and presumably registered as such. If we go down the OEM route (which is my normal path when I build a system), I dont want to waste the lady's money when it is rejected by the Microsoft activation process. Any views on this would be appreciated.

OEM edition doesn't really care when the computer was built, or if a different OS had registered that computer before. All it cares about is that the system it's running on is essentially the same system it's registered to.

You stated that the machine originally came with Vista and it was upgraded to Windows 7 Enterprise. If you buy an OEM edition-it will come with its own Serial Number/Key. Very important that you buy thru a Microsoft reseller/partner and have them guarantee that this will be included. It is essentially the same as the Full Retail version with several exceptions.
1. The OEM product is not supported by Microsoft-you become the responsible party for that. The cost of support calls, if needed will be higher than those for the retail edition.
2. The Retail license is handled in a somewhat different way from the OEM in that the OEM is tied to the motherboard serial number for the life of the machine. This should not be an issue with a laptop.

Hope this helps