Google this -> Disable Flash Hardware Acceleration.
But a desktop from 2002 may be too lacking to play today's apps. At least try the usual.
Hi i have a dell desk top from '02 and am using XP and within the last 6 months or so i am getting serious lag on flash videos not on youtube but sites like cbs.com for example... the video clips and never runs smooth while the audio plays fine....is my pc just old or is there something i can do to fix this thanks in advance!!