The old SHA256-based blockchain network is too slow and has been 51% Attack, more than 200Th/s have manipulated the network and reversed transactions. BitcoinClassic Team decided to switch to QUARK(POS/Masternode) to keep the coin more stable, faster and more secure. The new blockchain saves resources for the future. At this time, you can staking or creating a masternode, not the power of a computer.