USB pen drive - can't read the data

Hi,
This is Snehasis!
I have a 1GB Pen Drive. The thing is i can store data on it but can not read from it. I know the data is still in it but cant read.
How can i solve this problem?

Here is a soltution that can recover your data from your pen drive!
What can you do? Your USB Flash drive ruined!
Follow this
Get your data off it. Use Linux if you have to. Or ant pen drive data recovery tool.
Look on google for an article like "How a Corrupted USB Drive Was Saved by GNU/Linux"
Either way, do whatever you have to to retrieve the data back as
much as possible, if you're lucky, you should be able to get most
of it back.
See if you can repair the USB stick.
Some USB Flash drive manufacturers offer repair utilities to wipe your
whole Flash drive. (Essentially start from a clean slate.)
Look for a such utility from the manufacturer.
If that fails, you can use disk utilities to wipe the drive clean.
I recently had to do this on my Flash drive as the FAT began corrupted.
You can tell when some PCs are able to read the file, while others can't.
Or when you copy the file, you can't copy the whole thing, etc.
So if you ever have a Flash drive behave similarly, don't assume its
dead and buy a new one! See if you can recover and fix it yourself.