Lots of people are having the same problem (http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/T61-Nvidia-Quadro-NVS-140M-garbled-display-problem/m-p/46469). I did the reflow procedure, but, after 2 months, the problem returns. In fact, the g86-740-a2 chip is bad, and hot as hell. I don't think I'll buy another nvidia product again.
In order to repair my laptop, I bought a cheap motherboard (with Intel 3100 graphics, of course) with bios password. Now, my problem is to remove the bios password from my new motherboard.
First, i replaced the BIOS chip on my new board with the BIOS chip on my faulty motherboard. Unfortunately, it didn't work. The error message was "0192 System Security. Embedded Security hardware tamper detected.". There is no way to remove this message by configuration or software. The only known way to fix it is by replacing the motherboard (http://support.lenovo.com/en_US/detail.page?LegacyDocID=migr-42321).
It means that the BIOS chip is somehow designed to be attached to only one motherboard. In fact, there is a security chip (p24s08) that checks if the bios chip is the right one. Then, I replaced the security chip on my new board with the security chip on my broken board. It worked like a charm.
