So guys... i'm sorry if this have been thread before. but iwas just searching until 37pages i couldnt find.

following, i'm not a comp genius. specially mac. so i'm totally blind. yesterday i just bought a used macbook 2 GHz Intel Core 2 Duo, 2GB 667 MHz, Mac Os version 10.4.11. it just the notebook and charger only... and it is in german

question:
1. how do u change the sytem language?
2. is there a way to make it back to factory setting? will all the program installed also deleted?

any answers would be much appreciated.

thanks