Update Mcafee with Latest Update; and download latest Microsoft Malware Removing tool from Microsoft site.
Restart the PC to SafeMode, And Run the Microsoft Malware Cleaner and Mcafee Scan. You can solve the issue.
After that Restart the PC and check the Firewall status also.
I suggest you to run pc in safe mode, to disable System Restore, to disconnect pc from network and to run SDAT
2. Unzipp it via command prompt sdatxxxx.exe -e
3. Run it via cscan.exe /ADL /ALL /ANALYZE /CLEAN /PROGRAM /LOUD/UNZIP /WINMEM /RPTALL /report=c:\scan.txt
If the user is not much into browsing / downloading off the internet and primarly uses the computer to check emails, I suspect that the OS is no updated and could have open vulnerabilities that exploits use to infect the system. Please ensure that you update windows by turning on auto update feature from the control panel. ensure that you reboot the machine once the updates are complete.
In addition to this ensure that you update the Antivirus regularly (set the scheduler to download updates everyday) and set up a schedule to automatically scan the computer weekly.