Internet laptop is very slow?

A couple of weeks ago I noticed that when I go on some sites, the speed lagged a little bit. In the last couple of days it has gotten extremely slow on random occasions.

I ran a speed test and my download speed is often 0.50 mbp and a couple of other computers on my network are within normal range (15-20 mbps). My iPhone and iPad are on the same network and the speeds are pretty good too. Sometimes I can't even run a speed test because it times out. At the time I'm posting this, my download speed is 13.93 mbps, but it'll drop within a few minutes.

My ISP suggested that my wireless network card may be faulty. But Toshiba says it not because if it was, I would be kicked off the internet altogether, which isn't the case. Although my laptop is still under hardware warranty, they won't fix it. I'd have to pay $100 for phone support which is a ripoff.

I performed full scans on Windows Defender, Malwarebytes, and Trend Micro but none found anything.

I went to System Configuration, disabled a couple of startup programs, but there hasn't been any improvement.

I have full bars on the Wi-Fi indicator on my taskbar and the router is about 15 feet away from me. In fact I had an extra router that I switched to, but that didn't fix the problem.

I live across the street from a Starbucks and got on their Wi-Fi but it was very slow too.

I have no plugins on my browser (Chrome).

From what i've read, computers slow down as they get older, the internet to. Also on my computer i don't have a protection program like macafee because it slows down my computer way to much. What you could try dokng is deleting some programs and searching for ones you don't recongnize, sometimes the protection programs won't pick up things that don't harm your computer but slow them down. You may want to delete more usless toolbars, i'm not sure if thatll help but it makes sense.