🥇 Best Answer
if you have some virus in your pc then you can detect it using a antivirus software!
Why do u mean
system becomes slow
program’s stops responding
blue screen with memory dump
unwanted pop ups
Whenever your system is infected with virus then following conditions may occur:
1. PC stops responding frequently
2. Error alerts gets displayed
3. .exe files get blocked.
4. Unwanted toolbars get installed automatically
now threats are very models .
virus , malwares , spam , phishing , rootkit , backdoor , trojan , atp and etc .
must use good security software on any computer and phone & tablet .
How to know if there is virus in the laptop? Run malwarebytes . Google up download and install it on the machine. Then run a scan. www.filehippo.com is a good website, you can also download it from there. If there is a virus it will scan and find it. Later install AVG on your machine to ensure it will be safe from any virus attack.