Well an update years later, seems my 1.5 bitcoins have been lost completely.
Thanks Multibit!
Can you confirm you are running windows? I assume you are as you said hidden folders and files is switched on. What was the original version of multibit you had installed that lost your coins? The wallet file format changed at about version 0.4.0.
Have you used your computer much since you lost your coins? If you haven't there might be a chance the wallet files got deleted, but their private keys might still be on your hard drive. Don't boot from that hard drive anymore if you think the wallet files might have been deleted. The more times you boot from it the more chance there is that windows might overwrite your Bitcoin's private keys.
If you think the wallet files might have been deleted put your computer's hard drive in an external hard drive enclosure, plug that into another computer, and use the other computer to search it.
If you are running windows and didn't delete your wallet files try downloading and running this search tool.
http://www.softpedia.com/get/PORTABLE-SOFTWARE/System/File-management/Portable-Everything.shtmlRun it, wait for it to index all the files on your drive, then individually search for each of the items in this list.
.key
.wallet
.info
.cipher
key-backup
rolling-backup
wallet-backup
wallet-unenc-backup
If it shows any file or folder with a name including an item from that list then there might be a chance of recovering your coins.
Did your multibit wallet have a password? If it didn't then there might be other ways to recover your coins. Try installing a hex editor capable of doing a full search of your drive and use it to search for 08011220, which is a sequence of bytes that occurs in an unencrypted multibit wallet file 32 bytes before a private key in hex format.
These instructions explain how to search for those bytes in a corrupted wallet file, but you can also adapt and use them to search an entire hard drive, although that will be time consuming. If you deleted your wallet files, but haven't used your drive much there might be a chance that technique could recover your coins.
Since version 0.4.0 multibit classic wallet files are in a format called Google protocol buffer format (protobuf). Open a file with a .wallet extension in a hex editor and look for the following sequence of bytes 08 01 12 20. The next 32 bytes after that should be your private key in hex format. After you get your private key in hex format you can convert it to a normal format using an offline copy of the bitaddress website.
I tested this on an unencrypted wallet (one with no password) in multibit version 0.5.1.6 and it worked for me.
This is the hex editor I used, although any other is probably sufficient.
http://www.wxhexeditor.org/home.phpThis is the bitaddress website. I advise you not to directly paste private keys into it.
https://www.bitaddress.org/Instead look for this link at the bottom of the page and use it to download a zipped copy you can run offline.
https://github.com/pointbiz/bitaddress.org/archive/v3.3.0.zipThis is my multibit wallet file opened in the hex editor with the bytes 08 01 12 20 that precede a private key highlighted.
This is the 32 bytes of a private key (in hex format) highlighted.
This is the 32 bytes of a private key (in hex format) copied directly from the hex editor into notepad.
This is the 32 bytes of a private key after removing the spaces in notepad.
This is the private key copied from notepad and pasted into an offline copy of the bitaddress wedsite. Click the view details button to get the private key converted to normal formats.
This is my multibit wallet's address 1F84fkbMng6dJpGZmtycRbUe72B7XSYbeT shown on the right hand side of bitaddress. Every raw private key can convert into two different bitcoin addresses, which is why there's two.
This is my multibit wallet's address 1F84fkbMng6dJpGZmtycRbUe72B7XSYbeT shown in multibit.
You can import your private key into the wallet of your choice to get control of yours coins back. Electrum's a good choice.