This is just at a very high and abstract level of course!
Executable - No Shared Libary:
Client request to run application
->Shell informs kernel to run binary
->Kernel allocates memory from the pool to fit the binary image into
->Kernel loads binary into memory
->Kernel jumps to specific memory address
->Kernel starts processing the machine code located at this location
->If machine code has stop
->Kernel releases memory back to pool
Executable - Shared Library
Client request to run application
->Shell informs kernel to run binary
->Kernel allocates memory from the pool to fit the binary image into
->Kernel loads binary into memory
->Kernel jumps to specific memory address
->Kernel starts processing the machine code located at this location
->Kernel pushes current location into an execution stack
->Kernel jumps out of current memory to a shared memory location
->Kernel executes code from this shared memory location
->Kernel pops back the last memory location and jumps to that address
->If machine code has stop
->Kernel releases memory back to pool
JavaScript/.NET/Perl/Python/PHP/Ruby (Interpretted Languages)
Client request to run application
->Shell informs kernel to run binary
->Kernel has a hook that recognises binary images needs a JIT
->Kernel calls JIT
->JIT loads the code and jumps to a specific address
->JIT reads the code and compiles the instruction into the
machine code that the interpretter is running on
->Interpretture passes machine code to the kernel
->kernel executes the required instruction
->JIT then increments the program counter
->If code has a stop
->Jit releases application from its memory pool
As routeNpingme says, registers are set inside the CPU and the magic happens!
Update: Yeah, I cant speell properly today!