When using IE, it will randomly start opening tab after tab and I have to shut it down with the task manager. What is making it do that, and how can I get it to stop?

Do a Virus Scan

I had similar situation and eventually "fixed" itself, but the things I tried that may have helped the situation were a registry cleaner/optimizer

Ccleaner (Freeware)
Download CCleaner 2.09.600 - FileHippo.com
On the right hand side, click download latest version

And also, since this happened, have you restarted your computer?

So I would first use the ccleaner and then restart and see if issue continues