Problem with memory for T3500

I have recently purchased 12 Gb memory modules for my office W/S, a T3500. They are 6pcs of SNPDP143C/2GB (2GB 2Rx8 PC3-10600R-9-10-80). Modules installed in all available slots.

Problem is that the W/S doesn't pass POST.  Screen is black and I have a beep error code (which I don't remember now!).

I have tested the memory modules in my home PC (GIGABYTE GA-X58A-UD5 motherboard with X5650 xeon CPU and they works fine.

Bios version of T3500: A17.

CPU of T3500: W3530 xeon.

I don't know what to do.

Any ideas?

Thank you in advance,