If this problem just recently started you may also want to check with your internet service provider. It may be a problem with their equipment or their connection to your location. They should also have tests available to see if it's a problem with your computer.
It's difficult to suggest a magic application if you don't know why your internet speed is slow. If there's a problem with the wiring in your house, or a faulty modem, or a busy ISP server, no application will help you. Have you done any of the Microsoft suggestions or the speed test?
Also have you checked your antivirus program lately to see if you have a virus? Or even checked it to make sure it is doing scans?
Also download the free version of Malwarebytes at Malwarebytes.com, install and do a full scan
Virus, Trojans and spyware can slow down a computer via the Internet also
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Dell Computers
OS
Windows 7 Pro 32/64 bit and Windows 10 Pro 32 Bit/64bit