You have to completely disassemble the laptop1) Remove ALL power to the Notebook.2) Follow Anti-Static Precautions3) Remove the Display Assembly.Disassemble the Display Assembly, until you just have the Top Cover in your hand. (Gateway term = LCD Assembly Lid )2) Remove the Ram Memory, Wireless Card, Harddrive, Optical Drive, Keyboard Cover, Keyboard, Palm Rest, and remove the motherboard.{ Advise using an ESD wrist strap connected to a good ground source.Average cost is around $3 to $6.I connect, for example, to an unpainted surface, of the metal frame of an open, empty desktop computer case.Use a mutli-compartment container for the various screws you will remove.Label each compartment for the area the screw/s come out of.If no multi-compartment container is available, you can substitute with a clean egg carton. Label each egg holder.SOME screws look VERY similar to other screws.DO NOT mix them up! }Gateway NV53 series of Notebook PC's - Service Manual (Free),
http://www.tim.id.au/blog/tims-laptop-service-manuals/#toc-gatewayWhere it states Gateway 400, with 400 being in blue;go to the second line, and across. Click on NV53.This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.After you click on the file name (NV53), it may take up to 30 seconds before the first page comes up.For additional questions please post in a Comment.Regards,joecoolvette