7 pro/home mixup. more of a repair Q.

I have a system I've been trying to repair for a week.
It has an Athlon II 170u CPU, 4GB RAM, 64bit Windows 7 installed.
Service Pack 1 installed.

The PK on the side of the machine is for Home Premium.
The System Details screen shows Professional.

If I try to extract/check the PK from the registry with ProduKey, it shows "Windows 7 Home Premium"

~~~~~~~~~~~
On boot/login, I would get errors from a coouple of programs (groovemonitor.exe being the 1 I remember) concerning error code 0xC0150004.
I removed everybit of spyware/malware/crapware/toolbars/weather gadgets/shopping enhancers/search enhancers/language translators/etc. I eventually uninstalled every .NET I could, every Visual C++, Silverlight (actually I think Silverlight was one I couldn't uninstall).

I ran the installed McAfee. Removed it, installed MSE. updated and ran MSE. installed, updated, ran Spybot, Malwarebytes, superantispyware, hitman pro.

Hooked the drive up to another working, clean system, virus-scanned, ok.

SFC /scannow kept failing at 64%. I manually found and replaced the files than the CBS.log complained were missing from the store as well as the manifest.
SFC /scannow now fails at 63% :-(

Still get 0xc015004 at log-in. Now also get a dotnet 2.0.50127 (I think - 2.something) error.

Try to repair with Windows 7 OEM HP disk - it says you must be running Windows 7 SP1 to repair.
Try to repair with Windows 7 OEM HP SP1 disk - it says you must be running Windows 7 SP1 to repair.

Try to repair with Windows 7 OEM Pro disk - it says Windows 7 Professional cannot be upgraded to Windows 7 Professional.
Try to repair with Windows 7 OEM Pro SP1 disk - it says Windows 7 Professional cannot be upgraded to Windows 7 Professional.


~~~~~~~~~~~~
At one point I'd had enough and was going to do a new install - It was only SimplyAccounting, MS Office and Printer that I needed to re-install anyway. But the new install failed each time.

I ran memcheck86 and Microsoft's ram tester.
I ran chkdsk /r on each partition.

~~~~~~~~~~~~~~~~~
IE 9 is also horribly slow and crashes when displaying most Microsoft sites.

No helpful restore points and even the recent ones I was not able to restore to.
I was also not able to uninstall IE9 or SP1. I suspect it was installed with a SP1 disk and maybe someone tried to repair it before with a Pro disk.

~~~~~~~~~~~~~
Any ideas about how to force a repair install? Or fix the conflicting info between Computer Properties shows "Professional" but ProduKey shows "Home Premium" (and the windowsNT\currentVersion registry key also shows Home Premium).