Strange!!! Sandisk Cruzer blade 16gb

Hi.

I have purchase a sandisk cruzer blade 16gb a week ago. it had been working  flawlessly for 2 days but recently i copied some files from windows 7 64bit and connect that drive to a pc having windows xp. It shows usb not detected and has malfunctioned and blah blah. 

i thought that there is some problem in that system but i was shocked to see that now it was not even detected by my pc either.

After so many tries, i tried to connect it with my keyboard usb port and it was detected, however that port is not 2.0 because windows ask me to connect it to a hi-speed port of 2.0.   i thought the problem has been resolved and i format the usb and then connect it again to my pc. but same problem again and it shows device attached has malfunctioned. but when i connect with usb port of keyboard it works fine . however the usb keyboard to whom i attached this usb drive is connected with my pc usb port.

Similarly i have connect this usb with some old branded systems of Dell model Gx optiplex 260 and it was detected there too and at the same time not detected by any other pc which is unbranded…

Why is this usb detected now only by the usb ports of my keyboard and not by my pc as it was earlier detected by my pc.

I have tried many solution but nothing works even scan it with kaspersky latest definition.

Is there any solution to this problem. i want to connect this usb to my pc 2.0 ports.

I have intel DH55TC board with Intel I3 first generation processor. 

I got nothing on top of my head for this. Was this unit dropped by any chance? You might also want to call tech support to verify if this is defective and check your warranty.

Why is this usb detected now only by the usb ports of my keyboard and not by my pc as it was earlier detected by my pc

The only two possibilities I can thing of are;

Windows has assigned the same drive letter to the USB drive that it assigned to some other USB device.

There is insufficient power to support all the USB devices attached to the pc.

One of the contacts on the USB drive or port is oxidized.

First of All thank you.

Actually the usb is Defective and i had replaced it.

and Ed if it was the power issue then how can it be connected  to my keyboard’s usb port which ultimately connected to the same usb port of my pc and everyother usb drives like Kingston and Sony are working fine in that port.

Any ways thanks to you guys for the suggestion.