Thanks, but I was asking in a more general sense rather than an absolute. As the NSA is showing no software is 100% secure. 
I am talking about an acceptable level of risk.
Also, you might note that support for win2000 ended many years back bit there are still some 12% of PCs running it. Maybe not surfing the web, but msoft will still push out serious security updates as they did just recently over that IE zero-day or whatever it was.