I was concerned that my HDD may have been about to fail after I heard a couple of clicks (perhaps I was overly paranoid, but it's almost deadline time at University and I'm a Computing student - so having a PC available is a big deal!)
I bought myself a 2Tb HDD so I could do a disk image back up, and I also sent it to my local computer repair place to take a look.
They gave me it back, after testing the HDD, and said that it was 100% fine. (I've not heard the noise again, so I guess it was just a fluke) They said they took the HDDs out to test on their test bed, and didn't even boot up my PC.
I got it back a couple of hours ago, and it's hanging a whole lot (it had no problems before) and also being pretty slow. It doesn't seem to be very related to what I'm doing. It was hanging a few times in Windows Explorer, a couple of times in Skyrim, and once in iTunes. The hangs have been any time from a few seconds to a minute or two.
I ran malwarebytes and it found nothing.
It was a little slower than usual on the 'Verifying DMI pool data' on startup (It was usually just a second or two, but I noticed it being maybe twenty seconds one time, and five or ten another)
The PC had no problems before I took it in to be checked.
I'm receiving the error 'APPHANGB1' in windows explorer.