Damned virus makers

Having to type this on the mobile phone as the PC was infected with a virus that crashes the PC and then, once you reboot from your start up disc, it tells you the hard drive is going to crash and you must click on a pop up box to make a back up. I decided to make a back up myself via the Control Panel, yet the pop up box kept reappearing! Took the PC to the shop who took one look and said it wad a virus, leave the box with them, pay £40, and they'll ring once it has been removed...
That was Saturday lunchtime and I'm waiting for the call...