A nice explanation but no details on your comp or your rendering settings. What has changed? What are the render settings for the choppy movie? Sorry, you've given us a nice story with nothing to go on.
Hi Rick, from AE it was the default "Best Settings" 1280 x 720, Audio on AVI and in AME the YouTube preset. I doubt the render settings have anything to do with it - reason being, AVI movies that were rendered previous to this issue and have been watched many times without issue, are now choppy when watched.
As for what has changed, well I asked myself the same. I changed my keyboard and mouse to wireless. Also I deleted all my fonts and from another computer with the same OS, I re-installed the default set.
It may not have anything to do with the Adobe suite and more to do with my OS but I thought I'd ask both here and over at Microsoft and see what suggestions might be offered. I guess worst case I will look to do a clean install but I want to exhaust easier avenues first.
Check the various hardware acceleration options in the Quicktime control panel as well as Windows Media player plus your desktop graphics settings. Simple things liek changing the desktop theme or choosing anotehr performance preset in the graphics driver can have the weirdest sideeffects.
Ah interesting Mylenium, I will check that out as I did choose a new theme. Also it occurs to me that one of my external hard drives could be failing as it is where I render to and then play from. Thanks for the ideas.