Q: OS x 10.8.5 (12F45) connectivity

i have an older iMac, 3.06 Ghz Intel Core 2 Duo. Just updated a security update via Software Update, as well as the new iTunes. I have lost Internet connection. Have rechecked router and so forth and am writing this from an iPad connected to the same wireless. Have tried multiple restarts, zapped PRAM, etc.  Nothing works. Am I alone in this problem Or is it another Apple software update screw up?