Bet this happened because you just reinstalled WAMP, right? This happens if you did not back up the data folder under MySQL folder.
I am not sure if there is another alternative other than if your Windows backup is running. If it is, then you are lucky.
Simply go to the data folder and look for the iblog0 and ibdata files. Right click, select restore and choose which restore point you wish to revert back.
If Windows was not able to back up those files, you are out of luck.