We have already resolved this problem in earlier post but what if you do-not have an ISO/CD-DVD to recreate the bootable USB.
Note: Assuming you already have a windows 7 bootable USB.
Step 1. Download Windows Image tool Click here for the direct download link.
Step 2. Extract and run WindowsImageTool.exe
Step 3: Choose None at Source Path, connect your Bootable USB disc to the desktop/Laptop and select it at Destination path.