Ηι,
Thank you for your understanding - bad English - and for patience.
I was wrong, the processor has 2 cores and 4 threads.
Answers given me by the Forum of HP:
"Pretty limited processor selection so the only upgrade for you would be this:
Intel i5-3230M processor (2.6-GHz, 3-MB cache, 35 W)"
and
"They all should have 2 cores. Just so happens I bought one of those processors to upgrade a Thinkpad I own
not too long ago (successfully). It is actually the computer I am using to type this.
Just be careful buying a processor on eBay. Only buy from sellers with high reputation numbers".
Just like to seek a second opinion before I make the purchase....
Well, what is your advice, what to do?
Thanks again for your patience.