you mean when you turn on your computer Windows doesn't load or if you try to explore your files it won't open individual windows?
Also how much space in GB does your computer have in total and how much free space did you have prior to installing Hoi2.
In either case Hoi2 shouldn't have had anything to do with it, I suggest a clean format, reinstall windows, the updates, and then the Anti spyware, anti virus software, reinstall your games and it should work as good as new.
When was the last time you formatted it? Was there anything else did you do that may have caused it? Is it possible you have a virus?