Sony Vegas audio out of sync

Hi,

I have been using Sony Vegas for the past 5 months and haven't render a successful video yet! First it was "out of memory" problem and now "audio out of sync" issues.

The problem I'm facing this month is after rendering the video playback is out of sync. During the first few minutes of the video, there is no problem with the audio/video sync but as the video progress, the sync become worst, sometimes lagging as much as 50 secs..

The weird thing is: When I import the render video back into sony vegas 9 pro to play it, it play perfectly in sync.

Could my computer be the source of the problem?

Here is my rendering settings:

project template setting:

HDV 1080-60i (1440x1080, 29.970 fps) Audio sample rate: 44,100 ( using the match video method setting)

Rendering Setting:

AVCD 1920 X 1080 60i 29.970 fps ( Audio sample rate: 48,000) ( The problem, this rendering setting doesn't allow me to change the audio sample rate to match the project setting of 44,100, but its the only template I'm able to export HD after 4 months of messing with it)....


So my question is: The render movie is out of sync when playing with window media ( gradually become worst sync problem longer the movie)... But when I import the same "render movie" back into sony vegas, it plays perfectly without any sync issues...

Does this mean I have a cheap computer? :) Please advise..

Thank You in advance.
James