When I open Safari, I get a box with the Safari icon and a message to update: "softwareupdateproduct.com". I never saw this message before and it locks Safari unless, I guess, I click "OK". Could this be a virus?

When I open SAFARI on my MacBook Pro, Yosemite 10.10.4, I get a pop-up box with the a message that has the SAFARI ICON and says "softwareupdateproduct" and an "OK" box. I can't use Safari, I guess, unless I click OK. I never got this message before and I do not get this message on my desktop iMac when I open SAFARI. I am afraid this may be a virus. Is this a true Safari update? I have emptied my CACHES, but I still get the message when I open SAFARI.