I installed AVG free edition as instructed, did the full scan, found 18 infections, 16 of which were able to be fixed.
Rebooted laptop as instructed by the program and after 4 black screens and more rebooting, it loaded up like it normally does, and the desktop screen appeared for no more than 10 seconds - with the original "Corrupt File" notifications for my most used applications and programs - before it rebooted without me even clicking on anything.
Turned the laptop off, and on again, black screen happened alot more, and it's doing the exact same thing over and over again. At the time of purchase I couldn't afford a Dell repair package but it is still under warranty, but I honestly have no idea what I'm meant to do now, if it can even be sent away for repair at all. Can't access anything on my laptop at all, time between start-up and restart is getting quicker and quicker.
Help very much needed now and appreciated, thanks!