Another way to back your coins up is to manually create a paper wallet by going into your help menu and select the debug window option and  then the console tab....  On the command line of the console, type the command 'dumpprivkey' then your wallet address then you will see a private key generate...  Copy both lines of your private key and  wallet address and then repaste it in a Wallet.docx file and also physically print it out and there you have it, your paper wallet... No need to goto to a dubious website...  Assuming you've lost your backed up Wallet.dat file or your hardrive has crashed or files were erase you can load back your paper wallet into the network by simply going back to the console window and type in 'importprivkey'  then  cut and paste your private key address from your Wallet.docx file or manually type each Numeric Letter directly from your physical printed saved paper wallet (pain in the ass ) and your coins should appear once again.