Usb pendrive cannot read/write/open/ access

Sir,

I have two pendrive where one tells i need to insert the drive into the computer when i try to open it after inserting. When i go to properties it says used space 0 bytes and free space 0 bytes. I just cannot open or copy or read.

The other usb pendrive after inserting i open, it says i have to format before using. I see the properties, it says used space 0 bytes and free space 0 bytes.

Can you tell me what the VOLUME IS NOT PRESENT message.

Hope you can assist me .

Thank you

Armugam Tambusamy