wireless internet

[claud09]

when i first started using the wireless internet it worked find was getting around 200 kb/s witch is ok for where i live. in the last month my internet started spiking an lagging to where when i run a speed test off of speedtest.net it will go from 15kb/s to 125 kb/s it will go up an down up an down. the internet grid looks like a bunch of triangles. now i havent downloaded anything in the last month.
HERES WHAT IVE TRIED
cleaned pc / virus scan
checked for updates on router - wasnt any
defraged
I dont know anything else to do im using a desktop with a wireless adapter. thought maybe it was the adapter but i used a friends adapter an did same thing. so got me thinking about settings in router but i havent a clue on anything about it tried looking it up but just kept getting a run around was wondering if anyone has had this problem an if so how you fix it like i said it just started happing one day.

[LordOlives]

I would try using a wired connection and see if you get the same result.

Do you notice this type of behavior when your browsing/downloading or is it just during the speed test?

Have you tried using different speedtest servers?

If you have a second computer around I would try it on that one to see if it is also having the same problem.

If you haven't changed anything on your computer/network within the last month it could be something your ISP has changed, have you tried calling them about the issue?