i know the answer, go into your task manager (ctrl+alt+delete) then go onto processes and end WCSE or something like that ( a

Stop all unnecessary programs running in the background while you are gaming. Your memory is taking a big hit which is why this is happening. A few tips I can give you is if you have an anti virus installed set it to gaming mode if it has that option or turn it off while gaming and turn it back on after the session is over, disabling any extra start up programs (I had an old pc that took like 10 mins to boot and like 5 mins after it was in windows due to start up programs slowing it down.)

Try that and let me know, would help in the future if you can give as much information as possible though.