Not 100% sure it will solve your issue. You might want to give Windows Movie Maker a try (assume you are using PC XP or Vista). WMM can be downloaded free from Microsoft.com
Within WMM, you import your clip(s). In the monitor (where you watch the clip; also edit), you can pick a spot on the clip to "trim". The operation involves selecting the frame to set "Trim beginning" and then another frame to set "trim end". After that, you are done.
If you are on the Mac, iMovie should take care of that (I don't know much detail about this).
If a heavy duty video editing software is what you want (for long term, not just this project), you can take a look at Adobe Premiere Pro (free 30-day free trial can be downloaded from Adobe.com
Have fun with your project