I think this may do the trick, I tried it myself and it worked.
NOTE: This only works for the PC steam
Start Menu > Search 'Services' > Click 'Services' It uses gears as its logo > Find 'Steam Client Services' > Start it, then restart it > Wait 10 - 15 minutes > Restart PC > Wait 10 seconds after logging into user > Start Steam up > Paitience...
I did all that and it worked, not entirely sure if it will work for anybody else's steam but its what I did