Flashdrive Ununtu Installation
 

I have installed ubuntu in my 16 GB flash removable Disk. But now I want to remove it from the drive and so whenever I try to format it through windows it just shows me the left out portion of Disk(475 MB) only. I tried to remove it through the linux installation custom create layout in which all partions (/boot,/,swap) are visible. I tried removing them and made it free space though the pendrive shows only 475 MB space.

Kindly help

Don't just remove it, reformat it.

You have to remove the partitions. In Windows, you can use the Computer Management application, and select Disk Management. Select the USB drive, right click, and delete each partition (be careful you have the right drive!). Then you can repartition as one full sized partition and format.

I had tried this and have deleted all the partitions except the 465 MB NTFS partitions which is only being usable part of pendrive as of now. After deleting the partition became as "free space" and whenever I try by right clicking on free space partition to make it new volume, all the options it shows disabled(grayed).Help!

Don't bother with removing any partitions on the flash drive, just reformat the entire drive. You will lose everything that is on it but from what I can tell you don't want to keep Ubuntu on it anyway.

I had tried formatting still the problem remains the same...

Boot to live cd and try gparted or other such tool to increase the partition.