Yes, there is a space between the c / and forward slash. This scans your system files and fixes them. If you run the scan and see "found errors and fixed them all" you may see a difference in game and other program/apps performance. To be certain all files are healthy, run the sfc /scannow again. You should see the same message in my screenshot below.
sfc/ scannow should be a part of everyone's Windows system maintenance on a monthly basis.
