Originally Posted by
finncapt
Next time it happens, open task manager (right click the bottom bar).
I prefer "Process Explorer" (available free from CNET and others) over "Task Manager" as it is far easier to understand. It gives you more info on each program and more options for doing things with them along with some guidance if you're about to do something serious. I can use it and I'm not much into the tech end of things.
You may also be having some registry issues, which lead me to my second freeware recommendation of "Glary Utilities" (from CNET and others) which does a lot of clean-up work in a lot of places, again being very easy to use and understand. It will analyze and repair things for you as needed with just one mouse-click Between these two I was able to identify and repair something (can't remember what as it's been awhile) that was causing my mouse to lag and the OS to 'stutter' instead of flow smoothly. I've used the "Glary Pro" but the freeware seems to be all you really need- I won't have a PC without these two.