Guild Wars 2

I should begin six months ago, i hadn’t played GW2 for a few days and when i turned it on i noticed periods of lag that would occur every three minutes, i hadnt went back onto GW2 since then as i had a son and hadn’t the time but in the last week i have got a few free hours and have went back playing GW2, but alas, the lag problem is still there.
I have no trouble getting onto GW2, but after 3-4 minutes of playing, lag occurs and repeats every other 3-4 minutes. Sometimes however its more frequent and very aggravating.
I have tried every solution i could find to insure it was not my computer, by now my computer is old enough, but i never had this problem with GW1 or GW2 before, my computer is well able to run it and handle its specifications.
Solutions i have already tried include – checking for virsus, stopping processes to make sure my CPU usage wasnt too much, cooling down and cleaning the inside of my computer, lowering the settings of my computer and GW2, defraging my computer a number of times, removeing clutter and so on. But the problem is unique to GW2. While on GW2 however i notice a sharp spike in CPU usage, but as i said, i never had a problem with GW2 before.
Looking at other threads on here regarding issues around lag, i took an admins instructions and ran a diagnostics test (viewable in the attachment). I would appreciate any help regarding this issue. Thanks