Keyboard storkes dual characters when typing

[anbu13]

I had bought a ZEB-K11 keyboard and it worked fine on my Windows 7 for few days. And after a "Unexpected shutdown" my keyboard started to work bad. When I type something it types dual characters.
Ex: I type 'Hello' but it types 'HHelloo'.
Sometimes it works very fine.
I thought it would be the Windows problem so I tried in Ubuntu(same computer) and also in Ubuntu Live USB mode. Keyboard behaves like the same. I swapped USB ports but no help. So, I bought a ZEB-KM2000 & it works fine until another Unexpected shutdown happened. Now the new KB also does the same problem? Its very strange.What could be the problem?

 

[geofelt]

In the windows control panel, you can set the sensitivity of double click keys.

 

[anbu13]

In the windows control panel, you can set the sensitivity of double click keys.

Yeah I tried that too. In Ubuntu also its the same problem. It can't be a problem in Windows

 

[geofelt]

Then, it is likely a keyboard defect.
I would return it and try a different brand.
Amazon reviews are not too good.

 

[anbu13]

Then, it is likely a keyboard defect.
I would return it and try a different brand.
Amazon reviews are not too good.

I've changed from ZEB-K11 to ZEB-KM2000 & still the same issue. Would it be a issue if I connect it as a external KB?
I've not mentioned that I connected it with my Laptop Acer 5742G