RE: Unresponsiveness issues
You will have to do some troubleshooting.
The first thing I would do is monitor your CPU usage for some time (Task Manager). If the CPU usage is high when you are really not doing anything, the process list can tell you what process it is. It could be various things, but will most likely end up being some sort of malware.
The second thing I would do is look through the Event Viewer to see if any errors stand out. Run eventvwr.msc from Start | Run, search box or command prompt.
The third thing I would do is run "chkdsk /r" on all your drives. Please note that this may require rebooting and may take a long time (hours), so don't do it when you want to use your computer (if it works well enough to be usable).