satish,
Hacking a memory chip is when a crooked manufacturer takes a player with a small capacity memory chip and then alters the partition table on the chip so that it reads as a much larger chip.
He can then sell the player for a lot more money to unsuspecting buyers. In some cases people have paid for a 4GB player and in fact they only have a 128MB player.
When you start loading files on the player everything is fine until you start loading over the chips real size then the files start becoming corrupt because there is really no more room on the drive but Windows keeps reading the player as having plenty of free space and keeps loading files.
The problem you are having with file corruption is one of the signs of a hacked chip.
Try double formating your player with the MP3 Player Disk Tool which is part of MP3 Player Utilities. Open the Disk tool then go to the Partition Encrypt tab and move the slider all the way right and apply to format, then move the slider back all the way left and format again. If your player is hacked this will generally remove the hack and reveal the chips true size.
The other way to check your chip is to open your player and check the serial number of the largest chip against
THIS list of Hynix and Samsung chips.