I work as a computer tech, the keyboard replacement is a work I had done before on different models.
In short gateway said this to me:
since the keyboard is not a user replaceable part we are unable to send you the part.
In order to resolve this issue we can take your system for repair at a charge of $ 199, excluding one way shipment charges.
If you are interested please let us know.
Another option is you can contact a local technician.
That's funny because I'm the local technician.
I would be following S0ULphIRE advice:
some methanol or something similar and clean the contacts with a soft clean cloth.
Will let you know tomorrow how the work ended.