need to update to latest version of wordpress with lexicon theme

[dave4homes]

Hi everyone, i am using Lexicon theme and i am using wordpress version 2.9.2
i need to get updated to the latest version of wordpress, but the last time i did an upgrade, i had many issues, and lets just say I hate to do the upgrades, as it always has me cleaning everything up to get it to work and look like i want.

Can anyone just direct me to the most simplest way, IN LAYMANS TERMS - to do the upgrade- also explain the easiest way to do the back-up and how to restore the complete site after i do the back-up to the newest version-

i would really appreaciate any feedback I can get that would make this easy for me, without having to pull my hair out !

thanks
dave