Question Author
Thanks again, SlackAlice. I've done as you suggested but it's a little too early to tell if it's fixed the problem. I will however keep you posted.
One thing I will add is now that I come to think about it, I don't know if when the problem occurs, it also stops my keyboard from working. I have been reading that some people had similar problems with their mouse and keyboard after they upgraded to Windows 8.1 although this shouldn't apply to me because it's been a while since I upgraded and it's only during the last 5 days I've been having problems.
Anyway, that aside, fingers crossed my computer will be ok now.