Worse, it's... it's... I'd call it flickering, it's happening right now as I type this post up and it's killing my eyes.
I don't know what the f*** happened. This was going on yesterday, so I turned the computer off and then switched it back on today and the same story.
I don't know what could have caused it. I ran both Microsoft Security Essentials and Malwarebytes. They detected nothing, so I don't know if it's virus related.
I'm currently running a Windows XP service pack 3 computer, been with me for just over 4 years.
This has never happened to me before, and it's not subtle pc brightness flickering, it's very noticeable and very rapid. It stops doing that for a few minutes, then resumes immediately. I don't know what could have happened.