I was trying to comment to "[Solved]Opera keeps crashing 3-4 times in a row", but it was closed and not the best solve. Now my system is Linux but I sure the problem is similar. in the referenced topic they deleted the entire /.config/opera folder, but I discovered it actually one one file in the /opera folder "Preferences" had become corrupted by the sync function. Luck for me I had made a backup of the entire configuration folder and was able to replace with a yet larger then current, but close to original file by about 400kb in comparison to the original 341kb file.
The problem with not having a backup is you will loose most everything and be starting over with hours trying to get close to what you had. In windows if I remember the equivalent would be in a folder "AppData" somewhere in the user folder. You will have to change folder options to see this as they are hidden. Always pays to have traditional backups especially for windows because there system restore often dose not give what you need or want and is a real POS anyway. Of my 4 PC's only the laptop has Win7 to run only two programs and is backed up to one of my Linux machines.

I found the problem by making a copy of the effected folder and coping back a few files at a time, until the problem came back. It is Important to close the browser each time you copy of the new folder or the will not stick and be over written. As an example the new Preferences file will be about 40Kb and stay that way on closing the browser. Do not copy any .LOCK files as this will impede your efforts.