Computer hangs briefly and frequently for no reason.

Hello and welcome Kulle mate what are the temps in the system generally?

You can find them by looking in the BIOS or just running this
http://www.piriform.com/speccy/download

Kulle said:

I don't know if it is the same but there is a temperature display on the dashboard of my computer and that hangs around 25-28 degrees centigrade

Hum any chance of a screen shot of the Speccy readouts?

I'll get that to you as soon as possible but I may have found the problem. While scanning for viruses the occasional hang happened, but nothing as frequent or successive as previously mentioned. However, as soon as I started spectating a friend play LoL it hung around 6 times in quick succession. I went back to Diablo III and it did not happen there so I'm reinstalling League of Legends. If the problem persists after that I'll get you the screenshot

edit: did not work so I'll get the screenshot now. Just a thought though, every-time it happens the internet slows down, I get bad ping, and Skype disconnects, could it be network related (my BB provider is pretty terrible as well)

Yes nothing wrong there in fact pretty healthy. Well you might indeed have a problem with the ISP but I don't think it would cause the hanging unless this only happens during gaming of course.

Do you know what the download speed is? If not then this is quite a good app to have running

FlorianGilles.com - NetSpeedMonitor it sits on the right hand side of the taskbar and gives real time speeds.

the optimum download speed (according to speedtest.net) is around 6.81 mbps.
I should also add that my dad recently fiddled around with a new router, but it didn't work. We then reverted to the previous one but my internet has been significantly slower since (such as web page loading) but this could be due to a different position.
update: Almost sure it is to do with internet as it hasn't happened as much since and only when playing on line games like Diablo III and LoL. On League of Legends, I often have lag spikes of 2000+ ms, and only then do the freezes happen, but not so much as when I first posted this.
update: It started freezing very frequently on the loading screen of Diablo again so I don't know what to think... Perhaps a corrupted hard drive?

Well one other thing to try is a memtest after removing and reseating the RAM sticks this will show up any problems on the sticks themselves.

It does a fairly long time to do this testing and it should be run for at least 8 passes and preferably overnight. Just make a bootable disk of this and set the BIOS boot from the optical it will run in DOS.
Memtest86+ - Advanced Memory Diagnostic Tool this looks like it is going around the houses but am just trying to eliminate the obvious.