I have installed windows on an external hard drive ( it had very old photos), when i tried accessing the hard drive again after i have installed windows all the photos and data have been erased and the hard drive name has been changed to ESD-USB format...

It sounds like your external hard drive may have been formatted or altered during the installation of Windows, which can lead to data loss. Here are some steps you can take to try to recover your data:

1. Do Not Write New Data: Avoid writing any new data to the external hard drive, as this can overwrite the existing data and make recovery more difficult.
2. Use Data Recovery Software: There are various data recovery tools available that can help you recover lost files from formatted drives. Some popular options include Recuva, EaseUS Data Recovery Wizard, and Stellar Data Recovery. Install the software on a different drive (not the one you are trying to recover from) and follow the instructions to scan your external hard drive.
3. Check for Backup: If you have previously backed up your photos and data using any backup solutions like OneDrive or another cloud service, check there to see if your files are available.
4. Consult a Professional: If the data is extremely important and you are unable to recover it using software, consider consulting a professional data recovery service. They have specialized tools and expertise to recover data from damaged or formatted drives.
5. Regular Backups: In the future, ensure that you regularly back up your important files to avoid data loss. You can use built-in Windows backup tools or cloud storage solutions.

Remember, the success of data recovery can vary based on how the drive was formatted and the extent of data overwriting that may have occurred during the Windows installation.