ok so here it goes

i got a iphone 2g from US. it was unlocked when i got it and i insert my Maxis sim and was working perfectly.

then i connected my iphone to itunes and then i saw this update thing and i clicked on it. how stupid i was. i never knew that my i[phone wudnt work afterwards. i am totally new to these kinda stuff and so please help me out here.

that moment the iphone firmware was 1.1.4 and i was upgrading it to 2.0. what should do i next to make it able to use again?
do i have to downgrade 1.1.4? and will it downgrade the baseband aswell? i am using windows xp by the way.

after downgrading to 1.1.4 , how to to activate my iphone? how to unlock it.? and wat does jailbreak mean?

is it safe to do all these? will there be any risk of any applications not functioning properly after the procedure? if anyone had faced a problem, please care to share.

i hope u cud provide me with the answers.

thanks in advance!!
very worried,
ahm