Windows users have been put on alert after security experts discovered malware on millions of laptops that is almost impossible to remove, according to a report by Express.

And if you're wondering if your device has been affected and how to keep it safe, here's what you need to know.

It appears that more than 100 models of laptop computers produced by the technology company "Lenovo" are affected by 3 critical vulnerabilities that allow hackers to secretly install malware, which is almost impossible to remove or even detect.

The vulnerabilities allow hackers to modify the Unified Extensible Firmware Interface (UEFI), the first piece of software that runs when a computer is turned on.

This interface is the link between a computer's firmware and the operating system, and is present on a PC's motherboard, making it difficult to detect and even difficult to remove.

The study by information security company ESET found vulnerabilities in more than 100 different models, from affordable Lenovo laptops such as the Ideapad-3, to more advanced devices such as the Yoga Slim 9. (Yoga Slim 9).

Lenovo was informed of ESET's findings last October, with the Chinese tech giant releasing an update in April that should keep affected users safe.

Speaking about the threat in an online post, ESET said, "UEFI threats can be very hidden and dangerous. They are executed early in the boot process, before control is transferred to the operating system, which means they can bypass all actions of the operating system." Safety".

While the vast majority of affected devices are laptops that are still receiving updates, there are a number of older models that will not receive patches because they are not supported.

Advice to affected users how to stay safe, ESET said, "We strongly advise all Lenovo laptop owners to check the list of affected devices and update the device's firmware, following the manufacturer's instructions.