Format (reformat) the drive and see if that helps. 

If there is any data you need that is on the unit, copy that to the hard drive first.  Then then using the Windows Explorer, RIGHT click on the drive's letter and the LEFT click on "Format" and do a full format.

You should also use the "Safely Remove Hardware" function before unplugging the drive from the PC, rather than just unplugging when you are finished using it.  Sometimes the PC can wind up with an error for the drive's status then it won't work at all.  The Safely Remove Hardware icon should be in the "Sys Tray" (lower right) and RIGHT click on it.

Hi Fireberd,

I have formatted the pen drive 4 to 5 times using quick format option

and i use to click on safetly remove hardware always before removing the pen drive from the system.

is there anything i can work out with it.

thanks in advance for any guiance

Sounds like the Pen Drive is either filled close to capacity (which can cause it to take longer to transfer to) or it is going bad.  What I would do is transfer all of the files from that Pen Drive to a hard drive (or other media) and then see how long it takes transferring to it when it's empty.  If that doesn't help it open up a command prompt and type the following without the quotes:  "chkdsk/r e:"  Replace the e with whatever drive letter your Pen Drive uses.

It would also assist us if you could provide the exact model of your Pen Drive.  Not all Pen Drives are created equal.  Some are fairly quick and others are just slower than molasses in January.

Quick format is a useless command.  All it really does is mark all files as deleted without actually removing them.  It's biggest weaknes is that it does not do a surface scan like a regular format does.  NEVER use the quick format if you are trying to fix a problem.  A better solution is to use the chkdsk/r that I recommended in my first post in this thread.