yes, before anyone asks, i am a total thicko and dont understand any of this technical stuff.......
I thought i was doing my other half a favour when i plugged into itunes and clicked yes to upgrade....oh how wrong was i

....everything seems to have gone t*ts up and i am seriously in the doghouse for touching the said precious phone
can any of you experts tell me if i can put the damn thing back as it was ?????
all i know is that it was on 3.1.3, and jailbroken using blackra1n in december 2009, but now it says its 4.2.1 and 05.15.04
unlocking is not necessary but 3.1.3 jailbroken is vital because of some sort of programme job that only works on that ??????
please can you point me in the right direction to step by step instructions if this can be done.