After Around 5 Minutes Of Working After Startup, Windows 7 Completely Freezes

I've been using my Dell Inspiron 17R for around 2 months ago and it's a fantastic laptop, I mainly use it for videogames, music and movies/TV shows and it has ran flawlessly thus far.

Starting yesterday however, problems began to occur. I could boot the laptop up as per usual and access the Internet, play games, watch movies etc. but after around 5 minutes everything would suddenly become unresponsive. Both my mouse and trackpad wouldn't allow me to click at all, I could however move the mouse around the screen completely fine. The keyboard would also not work - I tried opening the task manager via Ctrl+Alt+Del as well as closing windows with Alt+F4 or trying to shutdown via the Windows key and nothing would work. Instead the cursor would change to the "loading" symbol and it would pretty much just do nothing.

The first time this happened I was browsing the Internet and it just got stuck on "Waiting for Cache" or something to that likeliness, I then noticed the rotating circle that shows a page loading had also halted and was then forced to reboot manually as I couldn't even click the Windows button. Another test I tried was watching a downloaded video - it literally just stopped playing around 4 minutes in. The screen just halted on a single frame even though the pause button hadn't been pressed - trying to click anything didn't work (as usual).

I tried rebooting it multiple times (I was sadly forced to use the power button) and it began to repeat every single time. It would work for a few minutes before completely freezing (minus the ability to pointlessly move the mouse around the screen). Occasionally a window would pop up above the task bar saying that the "Microsoft Windows application has become unresponsive". Sometimes the taskbar would then disappear and the laptop would shut itself down but the end result was always the same.

I found that the same problem did not occur when booting in Safe Mode with Networking, however there was some noticeable slowdown. I downloaded and used many anti-viruses/malware to scan my machine and I'm almost positive that there is nothing of the such on the computer (although in all fairness, the scans were running so slowly I could only make it to about 20% on each before giving up). Other solutions I've tried included:

1. Manually ending high memory usage tasks via the manager
2. Using CCleaner to fix my registry in Safe Mode
3. Left the laptop off overnight in a hope it would just fix itself
4. Unplugged everything from the ports of the laptop
5. Rebooted via the Restart, Shutdown and power buttons