Certain websites will either redirect to different site. Eg. I type in 'youtube.com' and it redirects to facebook or something.

Or, I will refresh a page, and the page will look like you just went (in firefox) and clicked View > Page Style > No Style. It is quite frustrating, and I've scanned my computer with Avast! Antivirus and come up clean.

I'm experienced with computers, but I honestly don't understand why this is happening. I've never had issues like this with any computer I've ever owned.