[swdw]

Before trying to manually delete the entries, download CCleaner , run it and have it remove all the entries it finds. If SH4 still won't install you can folloe Dolittle's advice being aware of the following

While the above advice is ok, the install code can vary from machine to machine the {{0D005F09-A5F4-473B-A901-5735C6AF5628}

It's best to delete the folders he mentioned, then do a search in regedit for silent hunter.

Start at the My Computer location. It will search and open the first key it reaches. If you have SH3 be sure you only delete the SH4 entries.

Anyway, hit delete key on your keyboard to delete the registry key and then confirm when it askes you if you want to.

Then hit F3 and it will take you straignt to the next entry for SH4.

You can do a search on ubisoft afterwards to see if anything with SH4 shows up after the first search. Delete any SH4 entries that show up on this search too.