How to set up T mobile internet on my laptop & why error message?

[catlover]

I am trying to set up T mobile internet from a USB stick on my laptop. I click on my computer & it says ' an unknown programme wants access allow or don't allow' I clicked allow & I had to choose a destination folder it had a default one so I allowed it, it started installing but then suddenly I got the message " Cannot copy files C:\Users\aaa\Desktop\T mobile net\T mobile Internet Manager, please make sure the file is not currently in use. Close any programmes and try again." That file wasn't in use as far I know.

Anyway I tried again using many different files & even made a new one but still getting this message. Can anyone tell me how to fix this & get the internet set up on my PC?