Doesn`t sound good so make sure you have backed up all your data. I would start by running System File checker - Start>Run and type "sfc /scannow" without quotes into the run box. Note the space between c & /
If this started recently I would try a system restore if SFC doesn`t resolve the issue.
As for the error on Mass Storage I assume this is an entry in Device Manager under Storage Control. This might point to a failing hard drive but let`s see what others think. You should do a check on the drive using check disc.