Yes ditch the celeron processor and get a Pentium 4 with HT, it's just too slow for video work and you need to upgrade to Service Pack 2 for Windows. A little bit more memory say One Gig would also be a good idea. Do you really need three hours of continous footage? The whole idea of video is to make a short enjoyable film rather than a James Cameron where your audience gets bored after half an hour and start yawning and looking at their watches.

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All done without the aid of a safety net...