Invalid digital signature on vista?

[xxdanielxx]

hey when ever i try to install anything from the net like quick time or any software i get invalid digital signature. I tried to turn off UAC for vista but same problem

 

[nickc]

do u get the option to let it run any way? I have had that happen on XP and tell it to go ahead and run it and have not had a problem if I knew where the program or install came from.