Problem with laptop strange black screen on boot!!

[bionic]

Hallo everyone.
Recently Im facing a strange problem with a friends laptop. It's an ACER Aspire 5740DG and two weeks ago it begun to show black screen when u turn it on. When you turn the laptop on, you can hear the HDD and DVD, the power led is on, the HDD led turns on at first and then goes off, the fun spins and the pc gets hot as normal and nothing else happens. No sound, nothing at all. The strange thing is that if you leave it on (with black screen), after 2 hours (!), you can turn it off and on and it works like charm. No shutdowns, no probs at all. You can even reboot it. So far I tried:
-Hard Reset (60 secs)
-Tested mems and HDD
-Plugged an external monitor (black screen as well)
-Bios update (It now has the latest driver 1.28)
-I unplugged both HDD and mems and turn it on. No difference, no beeping sounds or anything
If you leave it there for 2-3 hours and gets real hot (normal temp tho) and turn it on, it boots up normally with no errors and works completely normal.
+I Haven't tested the power adapter as it seems to works fluently (I had the laptop turned on for 6 days with no problem)
+The battery needs replacement, tho I have tested it with battery off as well.
Sorry for the long post. Any suggestions? Thnx in advance

 

[Digital Sage]

I've seen this before. Gpu solder joins have gone south. When cold it fails to engage the
Gpu on boot so you get some system operation but no screen. System stalls thou because it can't engage the gpu. So you leave it running, the whole thing heats up and the gpu solder joins expand / contract slightly and bang it's all good. Try reflowing the gpu.

 

[bertie40]

If you are left with no alternatives, you could try the towel trick.

Obviously backup all data. Wrap the machine in a towel, switch it on and leave it for a couple of hours.

Deliberately overheat it.

I've done this a couple of times and it has worked.

Longevity of the "fix" is obviously not guaranteed.