Every time I click on any .pdf file, WinPatrol immediately pops up with a random number string that is a mystery program it says is asking to be added to the Start menu; it's definitely Adobe-related. So I just click on 'reject' and it goes away and quits bugging me; but you have to disable the above-mentioned Adobe software -AdobeARM or Adobe Speed Launcher- from the Start menu to prevent it bugging you on a daily basis. Once again, many thanks to everyone who helped me so patiently, and especially to Dirhael.