In all seriousness, we'd need some more information before we can assist you in any reliable manner.
For example: Which operating system are you running? Windows 98? 2000? XP? Vista? 7? Under a virtual machine in Linux or MacOS?
With a "white screen", do you mean that the whole screen turns white? Or a fully white square? Does it have window borders/titlebar?
Do you get any sound? Been able to run it before? Have you been able to run any other Niffgames before? Have you extracted the game somewhere or are you trying to run it from the .zip? Running it off a USB memory stick?
Also, last but not least, do you think "Help!" is a descriptive title?
Rules in general: - Don't post topics with nondescript titles. Topics with titles like "Help!" or "I have a noob question..." are often pretty useless. When you have a problem, give as much information about it as you can, so people know what you are talking about and give it a helpful title so that people who might have a similar problem can easily find your topic via the search.