Even if you have a working and updated anti-virus program, it’s very hard to avoid a computer infection,once you are connected to the internet.
The buggers always find a way to slip in when no one is watching.For better understanding of the situation, let’s start with the differencesbetween “malware” and “virus”.
As we know, viruses are a special type of malware that is designed to replicate and spread in your PC, while malware is a general term used to describe all sorts of unwanted or malicious code.
Malware include viruses, spyware, adware, nagware, trojans, worms, and more.Here are signs to tell if your computer is infected andneeds attention.
*.Slow speed
Is your computer suddenly starts acting more like a tortoise and you’re sure it was faster when you first got it right? Try not to ignore that because malware has been known to slow down computers; taking longer to boot or programs take forever to open.
Another reason for slow system may be as a result oflow RAM memory and or low hard disk space, it’s best to check it out.
*.Pop-ups
Have you meet those annoying pop-up when trying toget work done on your system and windows start appearing randomly out of nowhere? It’s not random, it’s a virus.
A random virus maybe. These pop-ups have a tendency to carry in more viruses as they come.
*.Disabled security
When some viruses get into your PC, they cripple your defense. If your firewall is down, your anti-virus not functioning, then you have a problem.People are getting strange messages from youWell your accounts may get hacked, always make sure to always log out and set super strong passwords.
On the other hand, is a clear sign your computer may just be infected.
*.System crashes
Noticed lots of system crashes recently, are signs of bad health. Every time your PC crashes and a blue screen appears with a lot of jargon you don’t understand you better get that checked.
*.New browser homepage, new toolbars, and unwanted websites
Noticed new websites you have no recollection of opening and most times your home page gets changed. Malware does a lot without your consent.
*.Strange activity
You may also notice weird activity on your computer? Programs opening and closing on their own? Flickering and what not. Attend to any strange activity before it's too late.
When your YouTube videos are viewed on desktop computer, the google ad can appear on the right of the feature video and above the video suggestions list. It can also appear as semi-transparent overlay ad that appears on the lower 20% portion of your video as seen above. 
When viewed on desktop and on mobile, the ad can appear as skippable video ad which viewers can skip after 5 seconds.
Thereafter, click "Enable My Account"
Your video will go through a standard review process before ads begin to appear. If approved, you should see a dollar ($) sign next to each video via "Video manager". You can click on the $ sign next to each video, to change the enabled ad formats. Note that if you enable monetization at the time of upload and your video is set to private or unlisted, it will remain so and without ads until you make it public.