Simple sketches works fine on my Arduino Uno. In others words, it seems my Arduino Uno has no problems by itself. However when i upload my project, which includes both my original codes and the libraries of gps and music shield that is fairly big enough, the Arduino Uno totally crashes and has no responses.
Furthermore i guess it has nothing to do with logical faults because, in setup() function which is the first function that is executed, the first few lines is the ones that initialize Serial and send string for notification. However like i said before, Serial Monitor shows nothing, which means Arduino Uno doesn't execute the very first line. FYI. Serial Communication is totally fine. I mean the problem is not Serial Communication itself.
I think it's because Arduino Uno has small internal storage, especially RAM. Can i fix it by replacing Uno with Mega?
Atmega1284 has the most SRAM - 16 Kbytes, twice that of a Mega.
Get yourself one of my 1284 Duemilanove-like boards (not Uno-like merely because of the USB/Serial interface)
http://www.crossroadsfencing.com/BobuinoRev17/
Do you mean to say that it seems the shortage of SRAM is kind of causing malfunction?
Yes. Variables start getting written on top of each other, or on top of register, and then kaplooey, chaos.