About USB storage

Dear friends,

I want to ask something... I bought two Kingston's USB storage with each capacity 8 Gb... But it's only functioned normally for about a week... The first USB storage, when connected to computer, it could be detected but when I open Windows explorer, the USB drive isn't visible...

The second USB storage, when connected to computer, it also could be detected. But every time I explore the USB drive in Windows explorer, it always ask to be formatted. When I format the USB, it always failed with some warning "Windows was unable to complete the format"

Actually those USB storage still has the guarantee. But I bought it in China when I traveled there (I live in Indonesia). It's impossible for me to claim the guarantee. So I thought maybe I still could save them...

For any help and opinion, I would like to say thank you very much...