Processor Upgrade of Studio D540

I have herited a DELL DESKTOP D540 and was able to change this PC from 32-bit OS to a WIN 10 64 bit OS. Also the RAM upgrade to 8 GB worked well. Now I have the question if it is possible also to upgrade the current processor from INTEL CORE 2 QUAD Q6600 to a later new processor. If yes, which processor will fit into the motherboard and are there any other options.

Looking forward to a practical approach.