I all of the sudden can't see pictures in lightroom.

a couple of days ago, I loaded some pics to a folder. Try to open in lightroom and pictures never opened. I can see the folder, I can see the file number i just can't see the actual image to work on. I am not able to see the pictures in any of the other folders. I am not sure what happened, my screen froze for a second, went black and came back on with out the pictures. I deleted some folders with old pics thinking it was a storage issue, rebooted the comp and still no pictures in lightroom. I can see the pictures in my computer folder, just not in ligthroom. 

Can someone help me on what to do??