You have been transferring the Music and videos to the PSP and noticed some of your memory gone, you can get back them, follow the simple steps below

Open “My Computer.”

Connect PSP to Computer Via USB.

Go to Settings>Usb Connections(PSP)

Press X and watch the Computer screen and open the newly popped up icon.(thats your PSP)

Find your Movies, Saved Data, Photos, and Music, then take it all and copy it onto your desktop! Next go back to the My Computer and reopen the icon mentioned in

Go back on your PSP and go to Settings>System Settings>Format Memory Stick

Press X and ignore the warning unless you have not made a back up folder.

After you have selected to format your memory stick take your movies, Saved Data, Photos, and music and put it back on your PSP in the folders you found them in.

Grab your PSP and call it a day.

Note

Make sure you make the backup folder because you will have to delete all your information.