Startup short cuts now "security warnings"

[Rawns]

A strange issue has just cropped up on my Windows 7 PC. As of 2 days ago, any shortcuts in my "Startup" folder now present a security warning asking if I want to open them or not when my PC boots? There are only 2 shortcuts in the folder (My HP Print monitor & Netgear Wireless utility and both have been on my PC working for almost a year)

 

"Do you want to run this file?" [Run] [Cancel]

 

There is also no tick box to deselect "Always ask before opening."

 

When I click run, the programs load as normal. Any idea what could be causing this sudden prompt to appear?