Hello I'm using XP pro on Parallels 3 build 5608 on Leopard 10.5.4
Whenever I visit a flash site in IE it flickers badly. Does not happen in Firefox
This occurred on 10.5.3 with build 5608.
I suppose that either Adobe flash player is not installed correctly, or build 5608, or Parallels tools.
Try to start from flash player
if IE 7, reinstall IE 7,
Reinstall Parallels Tools
Reinstall 5608 as described http://kb.parallels.com/en/4790
