Hi. I'm Brian and I'll try to help.
That number does not appear to be owned by Microsoft. The resources I have state that it doesn't have a registered owner and that it's located near where Oklahoma and Kansas meet.
There's no such thing an "an infected IP address." IP addresses are just addresses. They can't be infected any more than your street address can be infected.
If you allowed someone to paw through your computer, it's time to back up your important data and reinstall Windows from scratch or from the Windows Recovery Environment.