@snaketibe: Yes it is possible to move just the model directory but you will need to edit your windows registry for this.
Alerte made a utility script to move ones collection this way. I also corrects the registy entry to match the new location. If you find the entry in the registry moving your collection goes like this:
Quit VGHD and make sure the installer also isn't running.
Move your Models and/or Data Folder to the new drive.
Enter the registry and correct the entry for Data Path and Models Path to the new location.
Start VG again. With luck your collection works directly, but sometime only the trailers will be seen but if you entered the right Path a check for news fixes this.
With the method JoaXim describes i really wonder why the heck to install as a new user when reinstalling. And if the support tells the users to edit their registry to delete the installid then they could tell them that the way i describe here also works. I think the above method only serves to raise Totems user numbers.
In the FAQ there is another method described that also works with uninstall and reinstall but without a new user and deleting the installid in the registry.
I copy it here too so you can compare:
"Reach the VGHD Data & Models directories (stored by default in C:\Documents and Settings\YOUR_USER\Application Data\vghd for XP and in C:\Documents and Settings\YOUR_USER\AppData\Roaming\vghd for Vista & Seven), copy and paste them to the other drive which would then be X:\VGHD (where X is your other drive)
Uninstall our software and then reinstall and watch for the option to change the data directory, its not a prompt, just a section on the setup screen.
NB: The uninstall will remove your saved (and encrypted) password, so you either need to have remembered what your account password was or to check on your password thru the Help section.
When you browse to select the drive X, it will display the new destination as X:\\. Do not worry about the second slash. You should then be able to re-update your rights and the models should not be redownloaded."
My suggestions if your not sure about editing the registry:
Use Alertes VGHD-Util Script you find on his website.
http://mapage.noos.fr/cumulus33/INTER/utile.HTMI just saw he also has a MoveVghd.zip there which might be exactly for this task.
You will not need to uninstall VG for this method. So no risk of not being able to install again and Alerte is very careful with his scripts and tests them thoroughly. So i absolutely trust his work.