t61p and blank screen on boot

[sagrailo]

Bought a T61p about year and half ago, and got it dual-booting between WinXp and Linux, and working very well throughout all of this time. The only problem I ever had with this machine was that from time to time the BIOS reported a stuck key on boot, but restarting the machine always get me past this. However, since recently, from time to time, machine just remain blank on boot; it won't boot (as I was waiting for couple minutes, and then trying to ping it, to no avail, from the other laptop in network), it's just that num/caps lock LED blinks, and then the screen remains blank. When it happened first time, I tried to reboot several times, and then just shaked it a bit (I thought it may be that something got into keyboard, because of these previous "key stuck" issues), and then it worked. Later, when this problem happens (it happens every 4-5 days, usually I turn the machine off at the evening, and boot it again in the morning), I was removing keyboard, and trying to clean the inside a bit (although there was not much dust there), and usually after several tries with re-attaching keyboard, and then pressing power button, it would boot. Today I went further - removed the fan, and cleaned it carefully (again - not much dust there actually), and I've changed the silver paste deployed between processor and fan, and between graphics card and fan. Again - it booted afterwards (actually, it booted when I tried it before removing the fan, but I went to clean up everything just in case), but I don't know how long it will take until the problem appears again. Note also that I've updated the BIOS to the latest version immediately after I recovered from the problem when it appeared for the first time.

So - did anyone had alike issues, and does anyone have any kind of suggestion what to try here? The machine is out of the warranty, and the guys servicing Lenovo machines in my country are not that knowledgeable - I guess I would have to give them machine for about a month, and then they would come back with Windows re-installed, and problem not even diagnosed at all... So I'd prefer to solve the issue myself, but I have no clue why the problem may occur (the graphics card, as well as connectors to the TFT, look fine); and after opening the inside of the machine for several occasions, I already damaged some screws (unfortunately, the build quality of Thinkpads decreased significantly since being taken over by Lenovo), and today I even broke some small plastic piece where one of the auxiliary fan fixing metal strips should be fixed...

Regards.