Scam pop-ups can attack your computer if you happen to visit a fake website by following a link from a spam email. You might have received the spam email through an adware or scareware through which you can accidentally acquire malicious codes if you download free software. Fraudsters even trick people using Apple and Android devices with phony alerts.

Fake tech support calls with fake warnings may also represent a rogue cybersecurity company with an unfamiliar name like Spy Wiper or System Defender or scam pop-ups often mimic well-known tech brands. To increase the fear of the user, the alert might also accompany a blaring audio or a long list of supposedly threatening files on your computer and they won't go away when you try to close your web browser. You will be urged to call a toll-free phone number to speak to a technician or click a link to buy or download (bogus) antivirus software.

Once the fraudsters are convinced that the target is scared, they will pressurize the victim to pay lump sum cash for repairs, new software, other products and services. They may ask for a credit card number so they can do the transactions or request payments by gift card or online money transfer. They might even try to utilize the access to your computer to transmit actual malware that returns personal and financial information from the device which they use for identity theft.

Fraudsters create lookalike pages; they set up fake download pages that look unbelievably like the authentic ones. You need to be watchful and decide for yourself.

When you click on the page links to a download, which of course is not the actual software, but certainly looks like as shown in the screenshot:

Fraudsters take extra care that they actually hijacked the real programs and inserted their own piece of code half way through the installation procedure where the user will start receiving warning messages and indicating a toll free number for tech support as shown in the screenshot. When you call this toll free number, the fraudster will answer the call pretending to be a tech support official from the original product organization. He will get hold of sensitive information or ask for transferring money to an account to complete the installation process.