Don't reinstall just yet. First thing I do when I have to hard-restart the computer for whatever reason:
Once Windows is up, go to Windows (not Internet) Explorer. Click on Computer, find your main hard drive. Right-click on it, then -> Properties -> Tools (tab) -> Error-checking -> click Check Now -> choose all options, then Start.
The computer will have to restart. The scanning process will likely take at least an hour, sometimes two (depending on speed of computer and size of hard drive), so don't do it if you'll need the computer right away.
This is no guarantee it will fix your particular problem, but it's a starting point. When the computer freezes, files can become corrupt and prevent all sorts of operations.
If this doesn't have an immediate effect try starting each browser without add-ons
to see if that changes anything.