First of all, your photos are not stored in Lightroom. They are stored on your hard disk somewhere, they are not lost.
Your catalog contains your edits and metadata — you need to find it using your operating system's search feature, the catalog's name ends with .LRCAT. When you find this file, double-click on it to open it.
I have found that file, but it says it was created yesterday just after the crash and contains nothing.
That is the only .LRCAT file on your entire computer, searched by using the operating system search feature?
If that's the only one found, then you would need to restore a backup of your catalog file.
It is the only one found, I just had to restore the back up.
Thanks anyway for the help, hopefully it won't happen again