How do i do this? i have non expansion downloaded atm and looking to further install the expansion but have no CD. I have the CD key except i think iv already used my 1 download from the blizzard site. help is appreciated!!!

Did you successfully install Diablo 2 Classic?
Then you should be able to install LoD with this installer: https://eu.battle.net/account/management/digital-download.xml?product=D2XP&platform=mac&lang=en-GB

yes it workd but i think iv already made an acc ages ago and i cant member it...

If you can't remember your account try to get new informations via your email?

tried and i cannot remember the question thingo and idk wut the 6 digit thing is

If you write there into your games list your cd key you will get a new one with 26 letters. It's called "26 digit key". It's just the same as your normal one except longer.
Then you need to remember the question

uhmmm well... i duno the answer to the question :/ soo...?

Tried some options out? I can't help you if you don't know your answer You've registered your cd key on the blizzard page before?

i think so, been so long, and yeah iv tried like everythin i know on the question :/

Try to register a new account and just use the old cd key. Maybe you didn't register yet and could use it again