UTC Time No Matter What

I know I can get the UTC time based on my computer's clock using the following:
Dim currentTime As DateTime = DateTime.UtcNow

However, this is totally dependant on my computer's current Date/Time. If I change my computer's current/date and time, this UTC method changes as well. For instance, if I change my computer clock to 3/15/11, the UTC times show 3/15/11 even if today's date is 3/31/11.
I need a way to get the UTC's Date/Time no matter what my computer Date/Time is. That way if the UTC Date/Time shows 3/31/11 and my computer shows 3/15/11, I can still get the UTC time to show 3/31/11.
This is important because many programs, including one I'm developing, have a 30 day trial limit. In most programs, this can be side-stepped by changing the clock on my computer. I want to store the beginning and ending dates in a database so the dates/times will not be changed, then compare the ...