cyrnel

In rapid order I'd look for any exclamations in device manager, a quick rootkit and virus scan. I didn't see you mention what you use so try <a href="http://www.f-secure.com/blacklight/try.shtml">blacklight</a> and <a href="http://www.bitdefender.com/PRODUCT-14-en--BitDefender-8-Free-Edition.html">bitdefender 8 on demand</a> respectively. Both are free. Of course there are many AV alternatives but bitdefender is quite good at repairing in case you turn something up.

Then run <a href="http://www.majorgeeks.com/download3155.html">hijackthis</a>. Use "run a system scan and save a log file." Paste it here.

As for the green lines, sounds like it could be a video overlay problem.
What media types are affected (at least list the extensions)? Just video or jpgs & gifs too?
What programs are you using when you see them?
Are the lines limited to the media area or do they affect the entire screen?

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195