Urgent help required ;

[irish1958]

Here is what I would do
Uninstall with the disc uninstall program.
Clean your registry
Clean your document folder
Make sure you have run the MD5 on your GWX3.0 download
Check the Ubisoft folder and delete any files in it, and then delete the Ubisoft folder
Check your Computer/whatever drive you OS is on/user/owner/AppData/Local/ and make sure that there is no Ubisoft or SilentHunterIII folder; if there is, delete it
Do a search for Ubisoft and Silent Hunter and delete any found files.
Defrag your hard drive.
If windows vista or 7, make sure you install in a folder outside of the program or program(86) folder.
Install SH3 then GWX outside of Program/program(86) into a folder called "Games"
Make a copy of the SilentHunterIII/GWX install and place it on a DVD or external hard drive.
My fresh install is 4.8GB, so you may need a double DVD disc. Or you could cut the Mods, Support and Document folder from the install to get the size below 4.38GB. Copy them to a separate DVD and then restore them when you need to reinstall the setup.
(In addition you may have to delete the SHIII Key in the InstallShield folder to get the program to install, which I had to do, as the InstallShield program kept reinstalling this registry key which make my OS think that SHIII was already installed.)
Once you have your copy of SHIIIGWX3.0, reinstalling is a snap, or having more than one install (with SH3MultiInstall) is a snap
I would suggest that you also have a copy on DVD of SilentHunterIII1.4b so you can experience the other major mods, which are different, but enjoyable.