Which computer operating system.
To look for flags (or error notices in WXP) you go to Start->Control Panel->System->Hardware->Device Manager
Then look near the plus signs on the left. If there are errors they will shop up as black or Red icons or warnings... usually indicating a bad or incorrectly installed driver.
It is good to assure there are no errors there before we go looking elsewhere..
Then you check for infestations by using your favorite good antivirus and antispyware scanners, or course.
But what is typical is that your router is defective. Sometimes it is merely a driver or firmware error. So the next step is to totally remove the installation, after having saved a fresh set of drivers and firmware on another computer where you can get to them. Reboot after removal, and reinstall the drivers and firmware. If you have them on disk, use the disk rather than the download, then upgrade the drivers and firmware online if you can.
Of course it can be other errors. If you are connected to an Internet Service, have the Tech support of the company to whom you suscribe look down the line into your computer for errors.
Also, look for loose cables or sockets...
The cable company will likely charge you $60 to $100 to replace that part, but sometime you can find them at repair services, or on eBay.
