T400 not powering on; no fan, no beeps, battery light blinks

[gsl]

Hi everyone,

I fear that my beloved T400 has bit the dust, just a few weeks from its 4th birthday (and just as I'm settling in to try and write my master's thesis). I fear the worst and have already tried several suggested fixes I've found online to no avail. I ask here as a last resort to see if I've missed anything before I go start digging through the couch cushions for change to try and buy something new.

THE SYMPTOMS:

It won't power on at all, and for no apparent reason. I safely shut it down the night before as always, and returned from school the next evening to find that it would not start. The green AC adapter light is on when it's plugged in, and when the battery is connected the battery light is orange and blinks off about once every two seconds or so. Pressing the power button does nothing either with or without battery--there's no sounds like the fan turns over, there are no error beeps, just nothing.

THE ATTEMPTS:
--I've tried the various "static discharge" methods with the battery unplugged--pressing the power button 10 times for 1 second each, then holding it for 30 seconds, 60 seconds, etc. Nothing.
--I've tried removing the battery, hard drive, DVD drive, and DIMMs, then plugging it in and trying to power it on. Nothing.
--I've done the above steps with the backup battery disconnected. Nothing.
--I've left the backup battery disconnected for 24 hours (main battery and AC adapter also disconnected) and tried to turn it on with the backup battery still disconnected. Nothing.

A CLUE?
The only thing I can think of that could offer any clue is that at least a week prior to this sudden death (possibly two weeks), the computer ran out of battery in a very peculiar way. I had about 15% remaining on the battery, which should have lasted at least another 30 minutes, and was trying to put in an order for a pizza before shutting it down and plugging it in. All of a sudden, I saw the battery gauge had dropped to 4%, and the computer just switched off in an apocalyptic cacophony of beeps that persisted even after I plugged in the AC adapter. I was so startled that I can't remember if there was any pattern or how long it continued. In any case, it booted up fine on AC, and in the intervening time I had it running mostly on AC with a few brief periods where it was unplugged and running on battery.

Switchable graphics (running on the ATI chip at the time of death), 8GB RAM, 128GB Crucial M4 SSD.

Does anyone have any other desperate things I could try, or is this the end? Thanks!

[ReCreate]

Is it possible that the power button has failed?

Have you also tried disassembling the laptop entirely, disconnecting all connections, blowing on them or wiping them with an alcohol swap, and putting it back together?

I find that doing things like this usually resolved mysterious problems like these.

[foghorn]

It does sound like a power issue though since the system doesn't want to boot into the BIOS start screen. So the power supply has probably turned. I hear that many people's OEM power supply fail quite often.
Have you ever experienced and BSOD, and or crashing when using your computer? Because a bad RAM module(s) could be at play.
Maybe try re-seating the RAM.

Another possibility is that the graphics card has failed, although I've only heard that happens quite frequently with older T60 machines. However, since your system doesn't reveal beeps errors on boot-up, that might not be the case.

[kony]

Same thing happened to one of my laptops. Motherboard failed and it was too expensive to repair it, so I had to buy a new pc.