Mad behaviour graphic card/monitors/comp (can't work!)

[sir-frac]

Need help, folks.

I have a workstation with a Nvidia Quadro 600: main port out to a Dell 1920 x 1080 (DVI-D), secondary Sony 1280 x 1024 (HDMI to DVI-D).

Yesterday I connected the tv set (DVI-D to VGA) to the main port to watch a film (as I did many times before) and suddenly lost the secondary monitor. It just went off saying no signal received...

When I went back to my usual config, the Dell (primary) was showing blue horizontal lines (yellow on white windows).
The secondary still not working. However the signal routed back to the TV set (1366 x 768) looked still fine, no lines (?!).

Later on I tried the secondary monitor on the main port, impossible to use, on and off constantly. Even reducing resolution (can't touch the 60 HZ freq).

Then I turned it on with the main port / Dell only I see the blue lines today still there, but when I click with the cursor anywhere on the screen... it turns black!.

Immediately I connect that main port to the TV to check and there's signal there...!

I'm afraid I have some severe problem, but can't even guess which component to replace.
Graphic card fan working well, I tried old and new drivers and also plain VGA.

Please help guiding me to see what the hell is happening here.

Thanks

 

[sir-frac]

Just to add some questions with the hope of tickling some answer. Please tell me your thoughts.

1) Why I don't see any problem when using the TV set as monitor through VGA? Because of its inferior resolution? Does it mean the problem is *not* the graphic card?

2) Why when I connect both monitors to another computer none of them work but the Dell works (badly, with blue lines and some blackouts) in this computer?

3) Why the Sony monitor set in the secondary port shows some image (badly) only when the dual desktop is set "duplicate" instead of "extend"?

Thanks, need help.