i am currently using wireless internet to browse on my iPhone but all of a sudden the phone screen goes off, and i cant see anything on the screen but when a call is made to my number it rings but i cant see anything on my phone.
Hard reboot it: hold the home and lock buttons together for about 10 seconds until it shuts off AND reboots to the Apple logo. At that point, you can release both buttons. If the problems persist beyond that, you may have a hardware issue. Try a restore at that point, and then a trip to the Apple store.
I can say, with near 100% confidence, that you do not have a virus.
The closest thing the iPhone's ever had to a virus was an Installer app back in 2007 that, when launched, displayed the word "shoes" and then crashed. When you uninstalled it, it removed several important files from /bin, which didn't do anything truly malicious, you just had to restore.
So for now, no protecting against rogue software or anything of the sort is necessary, nor does it really exist.
If there is some virus problem in iPhone then first of all you can scan with latest genuine mobile anti virus and then you can check that iPhone working perfectly or not. If then problem has been not solve then you can format iPhone perfectly.
If your iPhone has been jailbroken it can get a virus, in fact the first known iPhone virus/trojan was the Rick Astley one which affected iPhones that had been jailbroken where the root password had not been changed.