help jalibreaking and unlocking

[DigitalHackerx]

how do i get it to stock firmware. every time i try to restore with the firmware i downloaded it says that the firmware file is not compatible. so i just restore to 3.0.1 cause it wont let me use firmware that i downloaded.

[blkcadi]

to get it to stock, you just restore in iTunes. You only need the custom firmware ((redsn0w .ipsw)) when your jailbreaking it.

[DigitalHackerx]

so how many time could this take? whats something that could be wrong with my computer that wont allow it to work?