White screen, no matter what

Late 2011 MacBook Pro Unibody, OS 10.9.5, 16 GB RAM, various hard drives:

OK, after the Apple Gong, and the whiz-whiz of the CD-DVD drive, normal apple logo appears, the grey gear turns and turns, and then... the screen goes white, the two fans start running like mad, the laptop heats up abd shuts down until cool again.

This identical sequence happens:

1. With normal boot up.

2. After resetting the PRAM, NVRAM and SMC

3. With different known good internal drives (switching drives in this unibody machine is a 3-minute job). Wrist-strap used, etc.

4. With Safe Boot

5. With Recovery Mode, including Internet Recovery Mode

6. With Verbose Mode

Can start from an external drive, have rebuilt the directory using the latest Disk Warrior, have checked the RAM and other components with TechTool Pro -- all checks out OK.

I have seen this referred to as the so-called White Screen of Death, but all the supposed fixes (see above) have had no effect.

Any new ideas on this?

Oliver in Alaska