windows 8 compatibilty issue

[Virag]

hey there,i recently bought a DELL vostro 2520 model with windows 8.i installed norton 360 antivirus but had compatibility issue with windows 8.so i uninstalled antivirus.but now in my laptop windows defender is saying that my "real time protection and virus protection is turned off.so i m clicking on turn on but its not happening and its saying pc is at risk..
plz help..

 

[johnbl]

windows AV software turns it self off when another AV program is detected.
I would make sure I removed the old software (norton)
(download the Norton Removal Tool)
ftp://ftp.symantec.com/public/english_us_canada/removal_tools/Norton_Removal_Tool.exe
then turn on the windows defender service

windows key + R
service.msc (will run the services plugin)
find "windows defender service" in the list
set its startup type to automatic
reboot and see if it is working now

after you are done, you might want to scan your file system files for corruption
cmd.exe (as a admin)
sfc.exe /scannow (system file checker)