- What video card/chip do you have on your computer?
- What is the installed video driver?
- Is that the latest one from nVidia, or AMD/ATI?
- If not, download the latest driver from the nVidia, or AMD/ATI Web site, and install that.
Also, be sure to indicate if you've made any major changes to your computer -- like upgraded the operating system, added video software (including free software you found on the internet), added or replaced a hard drive or if this is a new computer that you've moved your files to.
It might additionally help if you'll tell us what model of camcorder this original video came from and what format and resolution it is. (If you don't know, open the file in a program like G Spot Video or Media Info and advise us of the codec, resolution and frame rates listed.)