As a computer tech with over 35 years in the business, I've seen a lot of Internet connection problems. That's especially true with WIFI.
The most common problem is in establishing a 'good' connection between the remote computer and the wireless router. Many people don't realize that just because you're receiving a signal from your wireless router, (AP) you still may not be able to log onto the Internet. Here's the problem.

A weak or noisy internet connection is usually caused by lost or scrambled data packets. These damaged packets are constantly being 're-sent' between the router and the receiving computer. This will slow down your connection considerably and could even keep you from getting on the Internet at all.

There are several ways you can improve these weak WIFI signals. The easiest is to move the wireless router. If possible, try to locate your router near the center of the building. I've picked up WIFI signals from as far away as 1,000 feet when there were no obstacles blocking the transmission. On the other hand, I've also had a hard time just getting the signal to go from one end of a house to the other. This can be especially true if the router is located on a different floor than the receiving computer. The more walls and floors the signal passes through, the weaker it gets.

If you can't locate the router near the center of the building, there are several other things you can do. First, try moving the receiving computer to a different location. Even turning it in a different direction may help. Laptops often have the WIFI antenna built i