my laptop wifi connection speed suddenly drops last night, all other laptops are fast, I just installed McAfee and scanned, no virus but the speed is still extremely slow. When I took the laptop downstairs, it seems much faster. It never happens before. This laptop on the second floor for more than 1 year and is always fast. Please help.
Try restarting the laptop and also restart the modem/router. Should it still be slow, check with the ISP and see if they made any changes. Also have them walk you through checking the modem/router for changes to the number of devices it uses, etc. Even they can have made such changes. Sadly, it happens.
Should none of the above resolve it, and other devices get good speeds, then try testing your laptop via Ethernet connection. Does it get better speed? If yes, then your WiFi card is probably going bad. You can either replace the internal one, or get yourself a little external one that connects via USB.