there are a few ways to activate. One is when windows finishes installing you just hit next until it is activated (simple enough if your internet is working correctly), next is to go through, if it fails finish anyways and then go and fix your internet connection. then it is start, all programs, accessories, (I think system tools, might just be in the accessories folder) then the activate windows Icon. That should work. The final way is to follow step two exactly then if it does not work you select the options that will have you call a representitive of microsoft. They will have a number there for you.
Wish I could be a little more detailed on how to get to the call microsoft option, but I have not had to do that very often. Hope this helps.