Every PC can mine assuming you have a respectable PSU, The graphics card however in most cases is important as well because that will be the component you will most likely mine with.
You can calculate your profits or losses on this site: https://www.coinwarz.com/cryptocurrency
I'd suggest you try zcash first then Ethereum, if you get fed up with all this information you have to search just ask here or use nicehash, it calculates the most profitable coin to mine.