Default [Q] How to unroot and upgrade from 2.2.2 to 4.2.2

Hi guys,

Am trying to do the above on a HTC Desire. But am a complete noobie at this kind of thing (put it down to middle age lol). I've watched you tube vids, read forums (cant get unrevoked) and no luck.

Can someone do a Dummies guide for this or a join the dots.

Thanks for any help guys.