A flicker that resembles field order mistake AVI - MPEG2

[Rudyard]

I am converting some old TV shows I have taped on vhs years ago to DVD.
I did the same analogue cap procedure I used when converting my home movies:

Capt using Leadtek 7800 VIVO video card RCA connections

Uncompressed AVI capture to seperate HDD

Import into Sony Vegas 5, cut out ads save markers for chapters

Render as DVD architect PAL Video stream with Upper Field First (thats what my home movies vhs captures needed to get rid of the crazy flicker when I encoded in Lower Field First and I read in a thread here that generally you find out if its Lower or Upper field first depending on your device and then it will always be the same for that device, it doesnt change tape by tape)

I use the 2 pass VBR at 8000max 6000 avg 192,000 min standard setting vegas sets for DVD (I realise I could probably lower that or change the resolution from 720x576 to 352x?? or whatever VHS resolution is but I havent yet figured out if there is a compromise on quality).

Anyway the problem is whenever there is fast movement when I burnt a test of this show on a rewriteable there seems to be a flicker very similar to that of when the field order is mixed up.
Im sure it is worse when I reverse the field order to bottom field first but it is still there when I use upper field first.

I dont understand what the problem could be as in the past if ive ever had a flicker I just reverse the field order and it is solved.

Any ideas for the flicker problem? I state it is only evident during movement not if it is a scene of someone talking and they are still.

Also there seems to be a bit of a ghosting or trail when people move, kind of like if youve ever seen an LCD screen with a slow response time (at least I think thats what causes the trail on LCD screens!).

Does this have anything to do with the motion blur settings? I never touch them as I dont understand them and just leave them as they are.

Thanks for any help.

**Edit: My C: (not my capture HDD but my drive with programs, storage and windows on it) is in need of a defrag but I am waiting to burn some large files before I can do an effective defrage (at the moment the fragmenting is virtually identical before and after a defrag and I read you need a certain % of free space for an effective defrag - is that right and what would the recomended % be??)

Just incase this is somehow effecting anything.

[redwudz]

Defragging is unlikely to cure the problem. XP doesn't really need the drives defragged that often when using video. It's more of a problem when you work with many small files. I try not to let my hard drives get more than about 2/3 to 3/4 full, just as a general rule. If you keep a drive very close to full, it will likely have more fragmentation problems.

Just a guess, but VHS resolution could probably be compared to about half way between VCD and SVCD resolutions.

Sorry, I have no idea about the flicker problem, but someone here probably has some ideas.