Can we use the processing power from one of the other pcs to my computer

The only thing even remotely possible is if you had applications specifically built to divide their workload over the network. For example, maybe a compiler that divvy up’d source code compilation by subsystem, then collected the resulting object code for final linkage. Not something you see every day. What you're not going to find is some direct way of "linking" these computers at the hardware level. Your only option is the network and distributed applications.