Hello again to all,
I have made some tests on the server, i have started it with a Live CD and checked the CPU's.
With the Live CD i can see and use both CPU's. After i have booted from the HDD the problem has appeared again and the sistem "sees" and uses only one CPU.
So, this is a clear software problem.
Please tell me wich are the programs / .conf's wich are responsable of the CPU.
(P.S. i have had this problem some years ago with a windows XP and a Dual Core PC. The windows was seeiyng only one CPU and i have solved the problem by changing it with another wersion).
Thank you all in advance