It makes no sense to think that by changing your system date or time you could "fool" the activation into working. In lay terms - it appears the activate program simply asks this server "Is the product X giveaway still valid" - the server responds "yes" or "no". If the giveaway is still valid - activate.exe goes ahead and puts the registration info onto your computer. (The activate program is specific to a certain giveaway - they are different from day to day).
Your local PC date or time is irrelevant. The decision if the giveaway is current or expired is handled entirely on the server end (which is how a few months ago - the giveaway could be extended by 5 hours, without requiring any changes to the downloads).
Note that I haven't gone to any great lengths to pull this apart - just observed it in use - and being a code jockey it's just how I would've done it.
As for "I am deleting this site from my favorites" - well if the first time to try something new, I had problems, yet thousands of "happy customers" served every day - I'd question if maybe I did something wrong. Still it's no skin off my nose. :)
Just my rambling 2c.