Why does Jenkins block websites?

[Chris]

Every time I try to go to youtube, or apparently any site that runs java or something, Jenkins replaces the url and brings me to a login thing for Jenkins. there's no way to login, or make an account. I have deleted all cookies, history, cache. I have scanned, and wiped, all viruses from the computer. I can't find Jenkins ANYWHERE on my computer, or anything about it online as to why it blocks websites.
Please help me!! This has been going on for too long!! I'm tired of Jenkins' crap!!!!
EDIT: I've already installed a bunch of different virus/malware programs, including malwarebytes. nothing has worked.

[Matt]

Download the free version of Malwarebytes and run a scan - http://www.malwarebytes.org/

That should take care of it for you.