I5 2400 problem

[SpagnettiEater]

I guys I havehi guys I have a rather strange problem with an i5 2400 .. I exhumed it from an old box to update my father's computer that mounts a Pentium g850, with the Pentium it works perfectly, with the 2400 the bios only boots if I disable the multiprocessor option .. becoming a single core .. any ideas?  it worked until a few months ago .. any damage inside?  I tried 3 different motherboards only start with multicore disabled .. sorry if I make grammatical errors, I write from Italy 

[YoungBlade]

It sounds like something has gone wrong with the i5 2400. You tried it in 3 motherboards and it still did not work, so the CPU itself is probably the cause of the problem. It is an 11 year old CPU at this point, so it is not too surprising if some part of the CPU has failed.

[SpagnettiEater]

 so I use it as a single core or as a paper holder, thanks for answering me