If its a universal problem and not program specific then I would look at your keyboard settings in System Preferences. Also it will be different if you are using a PC keyboard vs a mac keyboard. I have a PC keyboard and copy is Alt (key closest to spacebar) +C , Paste is Alt + V, but in windows its would be Ctrl C and V respectfully. If I plugged in the mac keyboard I would have to hit different keys for alt, ctrl, option, etc.