rahulmig , if you had formatted using the MP3 Utilities Disk Tool, then your player had been originally hacked. It is a 1GB chip hacked to show 4GB. There is no way of regaining that lost 3GB, as the chip physically is only 1GB.
If your player now cannot be detected by MP3 Utilites Upgrade Tool, then you will need to follow the Dead Player Recovery Guide here
http://www.mympxplayer.org/dead-play...ide-vt567.html
If it can be detected by the Upgrade Tool, then you will need to try every v9.0.xx series firmwares in the downloads section here
http://www.mympxplayer.org/actions-9...mare-dc37.html
As there are very limited v9.0.xx series firmwares, i'll suggest you try every single firmware.