Family Settings issue....pls help if u can

Due to the "3 red leds" death of my former xbox 360, i got one from gamestop (used premium 60gb). After turning it on with a wide smile on my face, i found out the family settings were activated by the console's former owner and i was unable to access xbox live and get my old gamertag back. I knew of a pre-XBE button combination to enter in order to reset the fam settings, but this does not work anymore. I tried to format the hdd with no result at all. I've already mailed ms but their response was useless, basically they suggested me to visit the site or give a call to the support number; site wasn't helpful and the phone service days are quite far, so i'd like to be able to retrieve my gamertag before friday

So...any of u can suggest me some kind of trick to reset my family settings, or any method to solve this (kinda frustrating) problem? Hope u can.

other than clearing the cache i cant realy think of anything. Thats the button command ur thinking of im sure.

MS support should be able to help you, since it costs nothing to them. Otherwise theyplay dumb.

Edit: you have to call them and always pick "other" option to talk to someone, automated help isnt very helpful