USB flash drive not being recognised anymore

Hi,
Last night i was copping some songs from my computer to my USB flash Drive & suddenly it got hang i don't know what exactly went wrong i stopped the copying process & after that now i cant access the pen drive. I mean when i plug it in USB port it emits the sound of recognition but don't show it in my computer. Anyone explain me what went wrong? Any solution?

Can you tell us what operating system you have? So that it will be easy to give you appropriate solution.
I think its an issue with currupt data or windows system.

I have Xp pro installed!

Well my guess was quite right then have a look at this
http://support.microsoft.com/kb/925196/en-us