I had a kingston pendrive of 4 gb but now it become 1.99 gb what i do???

Click start control panel administrive tools computer management disk management right click on your drive select properties click tools you should see click check now click start two boxes automatically fix files and scan for and attempt recovery of bad sectors place then a tick in one box then select check now start or you might tick one box then return after its finished the first repair then return and tick the second box I have found better results ticking the first box then return and tick the second box you should not do anything while the chkdsk utility is in progress any input may damage this drive also you might need to do this Click start click to open on my computer you should see your usb drive F: right click select properties there will be an array of options select the sharing tab option then advanced sharing make sure you have a tick in the share this folder box then click permissions make sure you have full control in windows 7 Click start control panel user accounts click on the administrators account if you have made one or you will have to create one in windows XP
also

If you are running a Windows XP OS then you might be able to:
Click start right click on my computer select open

Right click the icon of your Flash Drive (It should be F: / E: or something)
Click Properties in the menu that comes up
Click the Sharing tab
Click permissions
And finally, click Allow next to Full Control.
also you might need to do this Click start click to open on my computer you should see your usb drive F: right click select properties there will be an array of options select the sharing tab option then advanced sharing permissions make sure you have a tick in the share this folder box then click permissions make sure all three boxes are ticked you full control change and read in windows 7 Click start control panel user accounts click on the administrators account if you have made one or you will have to create one in windows XP
also
If you are running a Windows XP OS then you might be able to:
Click start right click on my computer select open

Right click the icon of your Flash Drive (It should be F: / E: or something)
Click Properties in the menu that comes up
Click the Sharing tab
Click permissions

And finally, click Allow next to Full Control.

you might have restore it to its defaults Right click on usb drive select properties you will have an array of options Select the hardware option then select your drive properties policies restore defaults In XP Right click on your drive select properties then on customize restore Default in W 7 If you need more help with this post a reply Hope this helps.