Suddenly my USB drive (EMPREX 1GB) is not accessible. It shows up when I open "My Computer" icon, but when I try to access it, it comes back with the error "The disk in drive in not formatted, do you want to format it". Certainly I do not want to format it as it has my
some important data which I might lose if I format. Any help in restoring it ????

thanx

Before you start trying exotic fixes, check to see if it does the same thing on a different computer.

If it works on the other PC, then immediately copy the contents of the thumbdrive to a folder on the PC so you have a backup copy.
Verify these backup files are valid.

Then you can try to fix the problem on your thumbdrive or the first computer without fear of losing your data.

First I tried this on all the four ports on my computer.
Then I tried this other computers with same result.

I don't want to lose the data on this. It is very important data for me.

thanx and regards,