clip rendering errors you say?
by chance...are your clip(s) encoded with divx or xvid?
if so...there is a workaround in vegas (that or magix), but I would suggest re-encoding
an explaination can be found
here.
getting more codecs won't neccesarilly(sp) make your video play
codec packs (with the exception of cccp, and matroska) are bad for various reasons, I would reccomend uninstalling them.
reccomended codecs (can be found using google):
Lagarith
Huffyuv
Divx (for distribution and playback...not editing)
Xvid (same as divx)
PicVideo MJpeg
optional (may be useful)
FFDshow
cccp (pack)
matroska (pack...may include FFDshow)
if english is your first language...please try to use proper grammar and sentence structure. I could hardly understand what your first post was trying to say
if not...try to post like the second post you made. much easier to understand.