please help me with texturing (blender and gimp)

hey guys so usually im fine downloading a texture and just putting it on the entire mesh no problem make normal maps and everything and it looks mostly fine (looks like crap where seam is if you got a brick texture or something)

but i have a bigger problem. sasy im making something simple like a computer desktop and keyboard. how can i texture the things like the buttons and disk drive and everything? . do i make a texture for the buttons and disk drive type stuff or is that something i should model and turn those parts into a texture instead of geometry? or do i draw it?

and for the keyboard ok what ill do is use gimp and remove everything so its just the text of the keyboard. once i match the uv to each key and everything is good. well how do i put another texture on the keys and it doesnt cover over the text textures? am i doing it wrong or something because it happens with normal maps too. ill bake a hole into the low poly and put another texture over and then you cant see the hole anymore really (in render mode)