Sven-

1. Vegas displays (in timeline and in preview window, while in motion or parked) only the first frame of a clip. clip is an AVI 320x246 uncompressed, no audio.

What did you use to generate this 320x246 avi?

2. Vegas display and renders are horribly artifacted - clip in this case is a quicktime mov 320x240 compressed with sorensen codec. does vegas need uncompressed sources(see #1!)?

No, Vegas does not need uncompressed source material, but it does need reasonably clean source material if you care about quality. More importantly, you need to use an appropriate codec when compressing. You are compressing with Sorenson "free version" which is pretty lame. Soresnon Pro (costs money) is the best QT compressor for streaming. Why do you need quicktime?

3. Vegas CTI (current time indicator) loops a very short section when I hit play. sometimes play will continue after a short time. other times, i'm stuck in the loop. yes, loop is off. in-out points are not a factor.

how often does this occur?

This PC also has CubaseVST and a Fontier Dakota audio card installed. No 1394 interface in this box yet. Sound Forge 5 and Acid 3 are working fine.

I must say that the above conditions have rendered Vegas useless for video. I have tried it on another Win2K box successfully, so there's something about my configuration that's screwing vegas up. this is so typical and frustrating. and it's not like i'm green here - i use discreet, avid, fcp, protools, etc. on a daily basis. what dumb thing am i missing?

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Post some detailed system specs, including irq layout and perhaps we can help further.

You need a good deal of free drive space. You also need to be vigilant about defragging the sucker. My advice is to pick up another scsi drive and make it the spot where you keep your source media. 9 gigs isn't much room at all when you're working with an OS, the other programs you mentioned and video soucre.

Have you updated your scsi drivers lately? Get the free version of winbench and benchmark your system. Compare it verus similar systems. If you're on par, you know the problem is vegas and, like Cheesehole says, re-install it.

Also - stay away from quicktime. It is optimized for the 68k architecture (aka Mac). If you must, import the QT and render to .avi.