RAM - Random Access Memory. The more of this, the faster a PC will run. The lower it is, the more sluggish it will be

GB - GigaByte. A measure of storage volume for data. In this instance it will refer to the Hard Drive. The more GB the hard drive has, the more data (music, pics, video's, documents, programmes, etc) you will be able to store on it

gHz - GigaHertZ. A measure of speed at which a processor (CPU) runs at. The higher the number in front, the faster it will run. CPU's are a bit more involved than just a number tho - a 2.8gHz Intel P4 won't run as fast (in real world terms) as a 2.0gHz Core Two Duo processor.

Notebook, notebook computer, laptop - all the same thing in reality.

What you want is a medium spec machine for what you want to do with it.

Something like a Dell Vostro (13.3" screen or 15.4" screen can EASILY be had for £300 with a decent spec....