That means that there is a program/process running in the background which is interfering with your game. It would have to be a program you installed under you account that isn’t on the new account.
I would first try disabling your anti-virus protection while you're playing.
You can try cleaning up unnecessary programs and processes too…Start menu -> type 'msconfig' into the search bar at the bottom. -> Everything on the startup tab can be disabled, by unchecking the boxes. None of these have anything to do with your computer running properly. It's still important though that you know what you're disabling. This list contains programs which are automatically set to start with your computer. Some you may want to start, like your anti-virus, but again there's no actual harm in disabling any above that. If you find unchecking something stops something you didn't want to, then you can always go back in and recheck the box. If you’re unsure what the processes are, run a google search on them.
Next go to the services tab. Check the box at the bottom left which says “Hide all Microsoft services”. Everything left can be unchecked just like the startup tab, with the same heads up. Make sure you don’t disable something you want. When you're done unchecking boxes click apply and then ok. It will prompt you for restart.
Also, what's getting in the way would be something you’ve installed or changed since the problem started. That may be a help in narrowing it down. Of course you could always just play on the other account. Up to you.. glad you have a fix for now though!