Just format. The problem is with all the web browsing, and installing stuff, you basically end up with a huge list of programs that are running in the background after a while, all taking up space. Here is my basic definition :
----------------------------------------------------------------------- (RAM)
|--------------------|---------|--------------|
(operating system) (random other programs)
When you run things, they get loaded into the ram, like above. but you only have a finite amount of RAM available. Every program you run needs RAM space to work, so the more you run, the more you need. When the RAM gets filled to the top, and if windows can not sort it out, because its doing something like sorting out all the other programs, the computer crashes...
In the case of your game, the .exe file is running several little programs to get the whole effect, and one possible reason for your graphics screw up is that the video section is not being allocated enough ram space by the OS.
Basic fix, you format the computer, so you have none of these other programs installed, start from scratch, and be careful what popups you click.
And if anyone actually reads this from top to bottom, they have a lot of patience... 😛 .