Find the folder that contains your Lightroom catalog file (it's name ends with .LRCAT)
In that folder is a sub-folder whose name ends with Previews.LRDATA. Delete this sub-folder. Do not delete anything else.
Thanks but how do I find that folder ? Is it by my docs?
Your operating system can search for files whose partial name is .LRCAT
THANKS SOOOO MUCH IT WORKED!!!!