Due to some reasons I formatted my pen drive and lost my important files.How can I recover my lost files?

How to recover deleted photos, videos,pdf, word,excel,zip,and other files from HP 32 GB USB Flash Drive v165w

Use “Undelete” to recover deleted files from pen drive Windows 7/8/8.1
Use “Unformat” to recover data from formatted pen drive

Use “Recover partition” to recover lost files if pen drive partitions changed or damaged or deleted.

Use “Full Scan” to restore important files from pen drive