pin 13 on new arduino uno .. seems to have a program called blink on it

so any way ,, how do i access the sketch for the pin 13 that must be embedded in the microprocessor that i purchased from arduino.cc.. now i have written a sketch for pin 12 to go HIGH (UPPER CASE lol) the built in pin 13 led has also gone high , but the but the output pin 13 has not gone high and does not blink any more .. so somthing is going on i don't understand

sketch for the pin 13 that must be embedded in the microprocessor

That is probably just the blink example from the IDE examples (in the IDE, File, Examples, Basic). Sometimes that code is added to the processor when it is bootloaded.

When you upload code to the processor, you overwrite the code that was there with the new code. The new code is not added to what was in memory, the new code replaces what was in memory. If you want the blink sketch back load it form the examples. If you want pin13 to blink and pin 12 to blink at the same time you will need to write code that does both.

so somthing is going on i don't understand

We can't see your code, and your description got badly garbled in transmission.