Acer 7520 - *serious* problem, please advise

Hi all, I am hoping I can write this before my laptop decides to die again! It's an Acer 7520.

Anyway on Saturday night I was using the laptop as normal and then I clicked on a link and suddenly the screen went all corrupted - I'd seen this sort of thing happen on PCs before (including this laptop) due to overheating, so I just assumed it was this, turned off power and then tried again a few minutes later.

Trouble is, the BIOS screen flicked up quickly and then I saw the same corruption. Lots of funny lines, patterns fading in and out, and a bizarre hissing coming from the speakers getting louder (it almost sounded like something sizzling inside!) So I applied new thermal paste to the GPU and CPU and then tried again. As the laptop had been off for a while whilst I did this, it seemed to stay on a little longer, but then when the Windows 7 loading screen appeared - bang - same screen corruption.

What lead me to think it is overheating is usually after 20 seconds or so of seeing this bizarre patterns, the laptop shuts off. However, I discovered something which leads me to think it's not overheating at all.

Bizarrely, the laptop works and boots fine with the lid shut!! Yep, when I have the screen completely down and locked, it boots, I hear the hard disk chugging away (something that seems to stop as soon as the screen corruption kicks in with the screen open) and then the Windows startup sound. I logged in without being able to see what I was doing (used a USB keyboard) and managed to get narrator running and navigated to GPU-Z - it said my temps were 61 degrees. This may sound high but I used to have issues on this laptop with temps in the high 90s, so this is a very good low temperature for me!

As soon as I open the lid however, there's the hissing sound from the speakers, and then the corruption and the system lock up.

I have two youtube videos showing what I mean:

http://www.youtube.com/watch?v=OyZGaQ4rADE&feature=plcp

http://www.youtube.com/watch?v=vx5AZ3CnnC4&feature=plcp

Any ideas? It seems it's not overheating at all.

Also, for some unknown reason, hooking the external VGA up to my TV does nothing so I can't even use it that way.

I just don't have a clue what to think here, I am good with computers but not the electrical side of them if there is some sort of fault, so I don't know where the problem lies here.

Any ideas would be gratefully received!!

Thanks,

Alex

PS - somehow I've managed to keep the laptop on to write this post (with the screen open) so I'm typing VERY lightly and carefully!!

ALSO forgot to mention, with regards to it maybe being a screen problem, this I can understand. But why would a screen problem make the PC unresponsive and lock up? I know it has locked up because if this happens during the POST or in the BIOS, the caps lock key does not light up, where as it does if I can see the display. So why on earth would a faulty screen/screen connection make the whole machine lock up? It doesn't make sense.

Thanks for the quick response. I don't have a external monitor at the moment sadly But I am hoping to borrow one tonight.

Well I tried it on a monitor (I didn't have the balls to take my laptop down to Staples lol) and I just get "NO VGA SYNC" from using the VGA port on the laptop, same sort of result as with my TV.

I am now back to believing it is to do with overheating, but if it is then it must be another chip or blown capacitor or something somewhere as my CPU and GPU temperatures (when I have been able to get into Windows) have been fine.

Is there anything I can look and check for? Has anybody every had a similar issue? I know if I take it to a repair shop they will just tell me the whole board needs swapping out, so it's not worth that, but I'd be pleased if there is something that might be able to be fixed.