This rapid flashing of the drop down menus in all programs is nearly disabling my computer which is XP on an HP Dual Core. When I open a PDF the side bar flashes insanely making the shinking and expanding text unreadable. The flashing drop down menus occur spontaneously without any input to them. Makes IE unusable, Favorites menus will not open or stay open. I downloaded Google Chrome and it is not affected. Ran several Windows Security Essentials full system scans; nothing detected or corrected1 person needs an answerI do too