Are you sure the pop-up is from your AV or the Windows 7 Firewall and not a fake AV trojan which you clicked on from a pop-up which has now infected your System. If so you'd want to run Combofix to repair infection.
There are other steps in posts 9 and 11 here which can overcome this type of infection: Fake AV infection - files hidden?
Normally Dell DataSafe Recovery will restore the HD back to factory condition when it is run, unless it offers to direct the restore to a named partition. Dell Restoring Your Computer´s Software to the Factory Settings
A better option for you might be to do a Clean Reinstall - Factory OEM Windows 7
while deleting the Windows 7 partition to recreate and format it during install. Everything you need is in the blue link.
Then follow Barman's procedure here to set up the Dual Boot so that GRUB can't corrupt Windows 7 as it can do otherwise when on the same HD: Dual boot Ubuntu-Win7