Do i have a VIRUS?

[Japsquad]

So wednesday i turned on my pc and went straight to YouTube to watch some video's. Everything booted up normally, but after about 40 minutes of watching video's, i suddenly got an error message from Windows on screen that my antivirus stopped working because of some .dll missing and i bunch of other stuff. I didn't know what this was, so i rebooted my pc. After the reboot, nothing would work. No startup program started, i can't open any programs, i would either click it and nothing would happen, or i get an error message that microsoft_common_control dll or something is missing. If it's a virus i really dont know how i got it, cause i am always very VERY safe while browsing the internet. The only device i connected to my computer not so long ago was my phone, and it is brand new. Can anyone help?
So because of all that i'm thinking of reinstalling my Windows 8.1, but everywhere is see it's important to use DBAN bla bla bla... Is it really necessary? Can't just use the format option in the installer? Cause i really don't feel like putting al the time and effort into using DBAN...
For those who wonder, i built this pc myself about two months ago, and it has been working flawlessy untill this suddenly happened.

Thanks for helping.

 

[vesp3r]

why rush into reinstall?
1st thing to try is restore to previous point
once restored try to boot into safe mode and run your antivirus to scan
if problem still exist when you restore then try running on-demand scanner to kill the malware
if still cant fix problem then you can start considering reinstall

 

[Japsquad]

I've already did system restore twice to 2 different dates, but that didn't work. I will try to boot into safe mode and see what i can do.