Garmin mobile pc key- 2 threads merged

[Gps nut]

Hello.
Just to let you know before i go on i am familiar with this program and have had this on several laptops.
I am using win 7 and i mistakenly installed mobilepc from a external hard drive using the main msi file.
It installed but not on my c drive but the external hard drive.
I uninstalled and deleted all garmin/mobilepc files i could find also in hidden app files.
I also did the registry.
I then copied the program to the c:/ drive and installed again only to find it went back to the external hard drive again.
Also it retained the same software id (which wont work with sw.unl ).
Is there somewhere i am missing that retains all info for loading mobilepc that is specific to win 7.
I have trawled everywhere in win7 apps files program file looking for an install temp file.
Also there is a line you can put in registry to fool mobile pc into thinking it is already installed but for the life of me i cant remember it.
Also does anyone have an original software only version that does not load from main msi but the install file.
Any ideas
Edit :- a new development.
I copied over mapsource program from my external drive and loaded it from c:/ drive and it to went to loaded to the external drive.
It might be a windows thing