seagate expansion portable drive model SRD00F1 500 GB capacity is not working and asking for formatting kindly help

Did it ever work? Did it have data on it already? If so, do you need that data?

I ask because the answers determine what to do. If it's a new, empty drive it may need to be initialized, partitioned, and formatted. If it has data that you need on it, those steps will trash the data and you should try recovery software instead. Try these threads:

http://www.tomshardware.com/forum/267620-32-best-data-recovery-tools
http://www.tomsguide.com/us/pictures-story/332-free-data-recovery-backup-restore.html#BOM_comments
 

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