Hola, voy a aportar mi granito de arena. Yo he conseguido quitar todas las contraseñas a varios portatiles Dell, y borrar el service tag.
Si tienes unos pequeños conocimientos de electronica, solo tienes que identificar el chip de la bios, soldarle unos cablecitos y seguir el manual. Está en ingles pero se entiende bien:
nope... you don't have to do that... just gotta jumper pin 3 and pin 6 on the "24c02", or "24u05", or the "24c164" or whatever chip resides in the location marked "upw1" (i think it stands for "unremovable password" lol) at least that's what it was on my D500... You really have to do some looking for it, mine was behind the PCMCIA slot.. only had to take the keyboard, one heatsink, and the pcmcia slot off.. then lift back the plastic, Carefully soldier wires to pin 3 and 6, then route them outside (i went through the fan opening), then put it all back together. then press the power button, short the wires for 2 seconds, then it "should" say "***Manufacturing Mode - Level *** Press Fn-X to return to normal mode" then when you see this, press F2, after bios comes up, press ESC, choose "Save and exit" then reboot... if "manufacturing mode" still comes up press Fn-X and it will exit that mode. you may have to mess with it a few times, but don't leave the wires shorted for more than 2 seconds. "the first time i did it i got a overheating warning, and it was gonna be shut down.. don't worry bout that, you've come this far, try it again... it actually came up for me by doing the following
Step 1. press power.
Step 2. short wires 2 seconds.
Step 3. disconnect wires, wait 2 seconds.
Step 4. short wires again for 2 seconds,
Step 5. disconnect and wait for "Maintenance Mode" text.
Step 6. Hit F2
Step 7. Hit ESC, Choose save and exit
Step 8. Enjoy your unlocked Laptop (with NO service Tag)
ok... got that straigtened out.. but now it says "service Tag:Not Installed" in the bios, so it will not let you save a new admin or configure password, but you can lock the harddrive, so good enough. (i can just imagin that call to dell support. "What's the service tag number?", "It says 'not installed'", "WTF, How'd you do that????") LMFAOTIPMP
So if anybody knows how to set a service tag, or what other functions you could do from "Maintenance Mode Level 1",
He observado que casi todos los portatiles Dell llevan el mismo chip en la bios, el 24c02.
Advierto que hay que desmontar totalmente el portatil, pues el chip está en la placa base pero por abajo. Para mas comodidad, despues de soldar los cables puedes arrancar la placa base solo con monitor externo y el teclado, y cuando hayas terminado la operacion, le quitas los cables y lo vuelves a montar todo.