Weird display problem... help! :)

[MrPolite]

could you look at the screenshot attached?
This is from a Dell 5100 Inspiron, with ATI mobility 7500c graphics card.
The screen looks fine for a minute or two but then goes bad, as you can see in the screenshot. I thought it was an overheating issue so i've cleaned up the whole laptop and re-applied thermal paste to the graphics card's heat sink.
Any ideas why this would be happening?

[vbcode1980]

Could it be the graphics card itself is damaged?
Or perhaps the cable or one of the connectors have been damaged?

[Hack]

Swap out the graphics card and see what happens.

[Siddharth Rout]

It is definitely the graphics card issue.

Few years back I had the same problem. I thought that the graphics card was heating up but that is not the actual cause. But I replaced the motherboard (it was a pc and the graphics card was inbuilt ) and it worked fine...

Try as Hack suggested. Swap the graphics card and everything will be fine...

By the way, Is the laptop under warranty?

[stanav]

Yep... The video controller in your laptop is bad... And too bad, it's built on the motherboard so you can't just replace it without replacing the whole motherboard.
You can try this:
1. Uninstall the ATI driver and just use windows's generic video driver... Most of the time this will give you the workable display, but viedo rendering will be a lot slower than using the ATI driver.
2. Remove the keyboard so that you can gain access to the motherboard. Check to make sure the heatsink is attached tightly to the video controller chip. I've seen quite a few laptop that have the heatsink separated from the video chip (because they use thermal tape to attach the heatsink to the chip, and over time, heat and moisture causes the tape not to stick anymore) When the video chip is not cooled properly, you can have distored graphics and/or system crash.

[MrPolite]

Thanks for the replies everyone.
I'll try to look into a replacement, but before spending so much money on this old laptop i thought i'd ask more: when i press the keyboard really hard, right above the graphics card, the image is back to normal again. That's why i had thought originally that it might be the heat sink not properly making contact with the card. I guess it could be the monitor cable as well? (but if so, why would it work fine and THEN stop working only a few minutes after the laptop has turned on)
any more thoughts about this?
thanks!

[MrPolite]

oh also it looks fine if i reboot! until another few minutes after reboot and it's all messed up again
It can't be a pure software issue since the weird lines go away when i press on top of the graphics card though

[Lord Orwell]

i had that exact image when i had a dirty pin on my video card. Somehow got something liquid on it at one time or another and eventually corroded while in the socket. looked exactly like that.
That's not caused by the processor of memory. It's memory itself or data transfer through a bad pin. If the processor on the card was overheating the entire system would lock up.

[MrPolite]

hey thanks again
come to think of it, this laptop had gotten wet at some point too :P so it's probably the corrosion as you mentioned. I can't find a way to get rid of the corrosion though :S

[Siddharth Rout]

MrPolite: Sorry to be the bearer of bad news but... you will have to replace it

[Lord Orwell]

hey thanks again
come to think of it, this laptop had gotten wet at some point too :P so it's probably the corrosion as you mentioned. I can't find a way to get rid of the corrosion though :S

if you can get the keyboard out, you may be able to reach some wires. The screen is hooked up by ribbon cables. Also you may be lucky and your laptop has a removable video card (panel on bottom).