ZBook G2 doesn't switch on with extended memory

[berndbausch]

My ZBook has 16GB primary and 16GB extended memory, 4 modules 8GB each. It has been running with this configuration for over a year.

Today, it did not start. After removing the battery and connecting power, the fan, power light, keyboard light and a few other LEDs briefly switch on, then off. After about three seconds, again on, then off. And so on forever. Meanwhile, the display remains dark.

Reseating extended memory doesn't resolve the problem.

After removing extended memory, the laptop boots normally.

When a single extended memory module is added, it doesn't start either, but the behaviour is different. After plugging the power cable, nothing seems to happen for a few seconds. Then CAPS LOCK and NUM LOCK start blinking in unison. Then the fan runs at high speed (I suppose the CPU is busy with something and gets hot). Display remains dark. This happens with either module.

I would like to have my full 32GB RAM. What could be the problem here? I doubt that two memory modules went bad at the same time (hard to test them right now). Is there documentation that helps?

Thanks much.

Bernd

[erico]

Have you run the available HP PC Hardware Diagnostics on youyr laptop?

Run a complete system test and then test the modules. 

Test all of the modules when they are in the primary soDimm slots to verify that the modules are not the issue.

If all modules pass the extended memory test in the Primary slots, the issue may be with the slot(s).

Is your ZBook still in warranty?

[berndbausch]

Thanks. It didn't occur to me to run hardware diagnostics. I will do that.

However, since the display remains dark when the modules are slotted in, I can only do that without the modules.

It's a generation 2 PC, from 2015 perhaps? Warranty expired even before I bought it.