I created a Windows 7 system with IE10 (which is out of date and no longer recommended by Microsoft)
Kaspersky security software
PADS VX 1.2
PartQuest
Kaspersky does not report an issue with my download of PartQuest.exe, and there are no certificate errors with this install. However you may have an older certificate causing an issue. I would activate a manual scan from Kaspersky to verify the details.
I downloaded a part, and added it to a design.