[Mashiro]

You are more than several years too late to jump on the Bitcoin train. Mining BTC by CPU is just a huge waste of resources (CPU cycles and power). The results are tiny amounts that won't cover the cost of the mining itself. So you make absolutely NO PROFIT but actually LOSE MORE MONEY. To mine BTC even with a little profit you need powerful GPUs with a lot of raw computing power (AMD). However nowdays the mining complexity is so high that people rather invest into specific miners (ASIC/FPGA) that are made for mining/hash crunching. These are expensive to buy but if you mine you will turnover a lot of profit at some point to cover the costs and still make a bonus.

If you want to waste resources you can mine other crypto currencies that can actually be still properly mined by CPU. Stuff like Monero, Etherium and others. Just search the web for CPU mining crypto currencies. Or as @rudra said contribute the power to something useful. In fact not so long ago, this year, researchers managed to make ground breaking discoveries (I believe in the UK or US) thanks to the computing power that was donated to them by users all over the world through stuff like SETI@home or BOINC.