If you had a balance showing in your Bitcoin-Qt before you backed up the wallet, that balance should still be showing when you restore the wallet.
A poster above alluded to a potential problem renaming the file - Windows by default hides the full file name from you (the stupidest thing ever). To fix this:
- In Windows Control Panel, go to Folder Options, the View tab,
- select 'Show hidden files, folders and drives', uncheck 'Hide extensions for known file types', uncheck 'Hide protected operating system files'.
Then you will see un-altered file names.
You must be 100% sure that Bitcoin is not running when doing anything with the wallet.dat file. The bitcoin data directory on Windows is
%appdata%\Bitcoin directory (a shortcut to C:\Users\
yourusername\AppData\Roaming\Bitcoin, or whatever your correct Windows path is). This is where the real wallet.dat used by Bitcoin will be located. Create a text file named
bitcoin.conf in that directory if you don't have one, and add these lines, to make bitcoin close when you specify and not accidentally run in the tray:
minimizetotray=0
min=0Close Bitcoin. Bitcoin also may take over a minute to close, be sure it is not running in task manager before doing anything wallet-related.
After all that, rename whatever wallet.dat file you have in the bitcoin data directory to move it out of the way. Then restore your backup, with the correct name, to this directory.
Finally, to ensure that you have a correct balance, when you start Bitcoin-Qt for the first time, run it with the command-line option
Bitcoin-Qt -rescan. It will take about 10 minutes before it starts up, as it looks through all blocks to find transactions and your actual balance.
If you do not have a balance at this point, your backup does not have the address, or the bitcoins are spent.
To see if the wallet even controls the address, in Bitcoin-Qt, go to Help->Debug Window, Console Tab, and type
dumpprivkey (using your bitcoin address). You will get either the private key if your wallet includes the address, or a red error message if it does not. If you do not have the address, then your backup is bad, perhaps taken before you encrypted the wallet and created another address, or copied while Bitcoin was running.