Having trouble downloading to laptop

I have Elements downloaded to PC, from original disk I purchased. I downloaded to sons laptop also.. He tolf me he downloaded it to his "thumb drive" so he can transport photo's to his school photography class. We went to download back onto his laptop but was told we exceeded limit and had to deactivate...  I went to add remove programs and uninstalled from his laptop, but it still is giving me the same message,, that I have to deactivate one of them,, even after uninstalling,,, can someone give me help??? Thanks