How do I get to do an online chat to adobe??

I need to contact adobe somehow. I'm trying to reinstall illustrator CS4 (as my laptop had to be wiped and restored). The install is fine, but as I have a CS4 upgrade it's asking for the serial no of the previous illustrator product. My previous product is Illustrator 10, which is not one of the drop-down options (CS, CS2, CS3 only). So I know the serial no is valid, I just can't enter it. I cannot find a way to initiate an online chat (it seems it has to be online as they won't support it by phone), and I need a way to bypass the "CS, CS2, CS3" option. I'm just being looped endlessly around the so-called "help & support" area. Any suggestions please (either how to contact them, or how to bypass the option list), before I completely lose my cool??