Can i run mining on one wallet at more than 2PCs?
Please clarify your question? Do you mean you are pointing 2PC's at the same address? Like -miningaddress="address" bc this is just fine to do.. Do you mean that you want to pool both PC's resources to the same wallet?
i mean that i will copy this wallet.dat to PC2 and run PC1, PC2 at the same time

I'm doing it this way and it works fine.