I enjoy making time capsule-type programs that shows something when the date countdown reaches 0, the only problem is that you can change your computers clock to prematurely make the countdown reach 0.

The only way I can think of fixing it is by connecting to a time server and getting the current date and time.

I don't want to have to do this, and I know there must be a quicker and more efficient way of fixing this problem.

Does anybody have ideas?

I know there must be a quicker and more efficient way of fixing this problem

I'm afraid there isn't. In fact, if you suspect user to change system clock, you'll always have to check NTP.

.NET doesn't have any built-in support for NTP but I found An SNTP Client for C# and VB.NET which might be useful.

HTH