Step 1.
DO NOT PANICIf you panic, you are likely to start performing actions without understanding the associated risks, and you could make things much worse. It is better to do nothing at all, than to do something that will make it worse. If the bitcoins are recoverable, then panic will not help. If the bitcoins are not recoverable, then panic will not help.
Step 2. Shut down the computer, and leave it turned off.
Things can't get worse if the computer is off. Software won't be able to manipulate the data on your hard drive and any damage to the hard drive won't get worse.
The next steps will depend on the type of laptop, and how comfortable you are with various software and hardware tools.
Effectively, your priority will be to access the hard drive in a way that will minimize the amount of activity (reading or writing) on the drive and recover a file named "wallet.dat". There is a VERY GOOD chance that the file is still somewhere on that drive, and that it can still be recovered if you haven't made things worse yet.
If you are capable of doing so, I would suggest removing the hard drive from the computer. Then purchase hardware for accessing an internal drive as an external drive, such as the following:
https://www.newegg.com/Product/Product.aspx?Item=N82E16812196455Connect the drive to a working computer and look in the Bitcoin Data Directory for the operating system that your laptop was using. If you can't find the wallet.dat file there, then use some undelete software or software designed to search a drive for lost data to search for deleted or lost files named wallet.dat. Id you still can't find it, then there is software that will search an entire hard drive for any and all private keys regardless of the filename.
Thanks for your replies and help so far. Very much appreciated!
So the most important thing for now as I understand it is to take out the hard drive and examine it from another computer with that cable and search for the wallet.dat file on it.
I will order a cable like that as soon as possible and leave the laptop off. I'm not touching it, I'm afraid to do anything wrong on it now.
Is that all under windows?
If so you may find a ".lost" directory, or find these files in the trash.
However, I concur with Hamilton's suggestion to turn the machine off and examine the disk from another machine.
No rush on this.
Right?
So do you have a 2nd available computer?
Yes, it all happened under windows 7. I used that laptop mainly only for the bitcoin core wallet and as an eventual back up laptop so I have indeed a 2nd laptop where I can work from.
So I should look for the .lost directory or files in the trash while I have connected my hard drive from another computer or from the laptop where the wallet is on?