I'm not sure if this is your problem or not, but I thought I would throw it in here - just in case.
Does your laptop connect with Wireless, network cable, or both?
I believe activation is based on MAC address, and your wireless and network cable would have two different MAC addresses. So - if you activated the WebAssist products when connected by wireless and then you try to use it when connected by Cable it thinks it's a new machine and won't authenticate.
If I'm am completely wrong about that I'll let a Web Assist tech correct me :) But I recall having this sort of problem a few years back, and I'm sure that's what I figured out.