No Hands SEO works fine on all versions of Windows from XP and that shouldn't make it run any different, faster or slower than any other version of Windows.
If it says loading then it is loading and likely just needs more time to finish loading. It could be that your database has gotten very large coupled with a slower machine, if this is the case I would suggest to leave it to finish loading and then
follow this guide on how to clean up an old database to help speed up the loading and running on slower machines. There is no need to repeatedly do this process, just run it once every month or two.