Thanks for your configuration, doyoun.
On my Windows 8.1 we use Windows Defender AV & Windows Firewall already built in. BitDefender is your choice. The Windows Firewall you now have, with Windows 8.1, is very effective at protecting your system. That is why only an older system needs a firewall as those recommended you earlier. One of the 1st security lessons I'd learned here was to set UAC,
User Activated Control, to "
Always notify me.." when/if something new will make "
changes to your system".
To activate protection from this go to the right side of screen to open charms and...
- Select "search"
- Type: UAC
- Choose: Change user account settings
- Move the slide control all the way to the top "Always notify". This gives User (you) warnings for system Account you Control. This lets you think & STOP before choosing "OK". When you are not sure, choose "NO", & wait until you do know what & why changes are being made before you open the gates to your computer "treasure".
This is what UAC means.
PS Good luck with IT!