Hi Brian,
I guess evrybody has different systems and software to protect it and sometimes this is the difference of viewing or not I guess.
Try turning off your anti-virus and seeing if it works with maybe windows built in virus especially as they say Vistas is much better than XP. Some anti virus(loads actually) slow everything down to much, maybe yours does that!!! Avast anti software is free
and is high on most peoples list as it does not slow down the progs so much.