A few sessions ago, I started getting some random multi-color pixels on the screen at boot. During some boots, I'd get colored patterns on the screen briefly. Then, last night, the machine froze on me. It was late so I just powered down and went to bed.
This morning, the T61 would not competely boot into Linux or Windows. After multiple attempts on both operating systems, I went into the Linux boot menu and booted up in safe video (lo-res) mode. It's been operating over 6 hours in this mode ok.
I'm thinking the Nvidia 140 card is bad. Is this something I could replace myself or is this a depot-only repair?
Sorry you're having this trouble, it is a well known issue. Unfortunately the only real solution is to replace the system board.
If you have a warranty on the unit, then send it in ASAP, Lenovo will replace your board. If the unit is out of warranty, then I may be able to help you with either a used board, or a reasonably priced replacement laptop. Send me a PM if you'd like to discuss your alternatives.
I have a guide I'm designing to deal with this specific problem, since the cost to replace a board from Lenovo is about $575, which is more then the units resale value. Don't feel all is lost though, there are less costly aoternatives and the real beauty of a thinkpad is the availability of replacement parts.