T530 randomly powers off when using USB 3.0

[chownrusbase]

Hi all,
I have a T530 that has been powering itself off. It's like someone takes out the battery or unplugs it; very fast. The only correlation i've seen is when i have had something plugged into the USB 3.0 slots on the left side.

This happened three times while using Windows 7. I had both a wired and wireless mouse plugged into the USB slot. The computer booted up worked for a few minutes then hard shut down.

Lately, I've been running Linux from a USB thumb drive, thinking maybe it was a driver issue. With this setup, i have a wireless mouse with its receiver plugged into one of the USB 2.0 plugs. Running for a while without any problems. Today, I plugged the thumb drive into the 3.0 slot, booted up and the computer shut itself off after a few minutes. I rebooted, but it happened again. I moved the thumb drive back to a USB 2.0 plug and its been running fine.

So, it doesn't appear to be a driver problem. I don't THINK it's an overheating problem. I pulled up lm_sensors in linux and i see:
core 0: 55C
core 1: 46C
which i think are well within normal operating limits.

am i missing something else here?

thanks,