Without getting too technical I'll try to provide a general answer to your question.
The amount of RAM that can be installed on any given system is determined by the ability of the hardware components (ie. CPU) to be able to access the address space for the RAM. More RAM necessarily contains more specific adresses (each location for storage in RAM requires a unique address space for the system to reference and utilize it)
In summary, if your specs say the maximum RAM is 2GB, regardless of the number of slots and size of RAM you insert into it - it almost certainly won't work. It's a safe bet that any manufacturer would give a specification for something so critical as RAM that would be less than its actual maximum.