Match time glitch

I wanted to change my time on the computer because it was inaccurate and as a result when i look to see how long my friends have been in a game it comes out as some bizarre number even after i restarted my computer. For example instead of 30:00 it would come out as 211:00 or something along those lines. Can I get some help, is there a way to fix this without reverting my old time?