Okay, I was watching anime earlier, and I suddenly got bombarded with antivirus warnings about there being viruses in my computer. Being a tech genius, I tried restarting the computer and that didn't work. Whenever I try to go on the internet on that user, it doesn't let me go on anything, it just redirects to a site that sells antivirus stuff. It only happens on that user though. I know almost nothing about computers, so do I have to buy some antivirus crap, or can I just delete something and make it work again?

You have a Rogue Software on you computer.

Run Malwarebytes.

If that doesn't solve it. Run SUPER antispyware.

It that still doesn't solve it, run Run Combofix

I suggest you to use microsoft security essentials.
it is easy to use. light in memory and the best part is its free so you can download from microsoft official site and update it free.