the clock

 I have had several people play the clock on me..(wait until the time on the clock is so low that when they move the game is over...and of couse they won that way  ...how can this be prevented?  sometimes there will be moves made that I didn't make ....and I have had pieces disappear ..I am not sure how the clock operates because I am relatively new here

I don't know what's going on, I don't play Live Chess. The clock should only run for you when it is your move. As soon as you make your move the clock should stop for you and run for your opponent. I don't know about moves you didn't make and pieces disappearing. The only time your pieces should disappear is when they are captured by your opponent. 

 people are waiting until the clock has almost run out and then they move...I have had pieces disappear when moving them..I guess i'll have to continue on with what I'm doing..it could be worse 

This doesn't make sense.  What you are saying sounds impossible.  Like the other guy said, when its their move.  So if they are not moving then they lose time and your time isn't going down.  So they will lose the game if they do that.  Maybe you are having some kind of browser refresh problem (don't know).  If you think its their move and your time is going down, then they have moved and perhaps you didn't notice which piece moved.

Long story short ... if you time is going down, then its your move.