I am running w' window's 7 and had it running with compatibility set to vista I think. Even then it would occasionally not open at all. Then I did a reinstall with the program directly on the C drive and NOT in the program files folder ei: C/Ubisoft/SH4 (This was a suggestion from one of the other skippers here and it works, or at least helps a lot).
Now the I have no problems with it. I might suggest doing one reinstall like this and if you still have problems
then use the compatibilty feature.
Hope this helps.
D40