Why is the internet speed slow on my laptop?

Question

laptops

The laptop has very low internet speed. My norm is 70-80 mb, but recently it has become like this:

It doesn't matter via Wi-Fi or by wire. No programs that could use the Internet did not include. There are no browser restrictions either. Internet is fine on the phone. Nobody can find viruses. The speed is not always so bad, according to the mood.

Answer 1

Downloaded Dr.Web CureIt, found some kind of virus and now it's normal

Answer 2

1. The cable is damaged
2. The signal is weak
3. Channel interference
4. Speed ​​limits on the router by MAC address
5. Transmit power is low on the router
6. Transmit power is low on the wifi module in the laptop
7. Someone is sitting on your router to the left
8. Incompatibility of wifi type on router with laptop card (b/g/n)
9. Loops in network settings
10. Router is stupidly corrupted and buggy
Check it all over again. Without details - fortune-telling in the thick of coffee.