iphone 3g no service/wifi

i have my sisters iphone 3g here, was gonna use it for a couple of weeks as mine broke and i ordered parts to fix it, i tried to jailbreak it and activate it as she was using it on a different carrier than i will be, as 4.2.1 was the latest ios on it that i could put on it i downloaded it used snowbreeze latest version and jailbroke phone, only problem is now it is showing no signal all the time and will not pick up any wifi networks, i tried messing with the baseband with the new redsnow but nothing has worked as of yet

any ideas

When you go to Settings > Wifi - do you see the WiFi switch greyed out?

i have the same issue as OP, i don't think his wifi is greyed out, it just isn't picking up any wireless networks.