Yes, it's probably best to call in support.
A couple of things you could
check out in light of certain characteristics of radio transmission .....
With both router and receiver are "fixed" (or non-moving) ... in a place ... it's very unusual for the signal strength to change. If you were driving in a car, it would be pretty normal but ...when everything stays put ....electronic components DON'T -as a rule- change their signal strength. They either work or they quit, but don't vary in between.
HOWEVER ....... if the two antennas (one on the router and the other on your wireless card) aren't lined up with each other, you CAN get "multiple path" effect ...... where signal is being bounced off of surfaces from different directions at the same time ...... which can contribute to interference and cancellation-of-signal effect. (Remember in the old days when you were watching TV from a roof antenna and a plane flew over and 'whoop, whoop, whoop ...... your picture would shift and snuff on the screen? That was from multiple path interference ..... ie ........ signal arriving from the station and also being reflected from the airplane body and coming from the plane, a slight amount of time later than from the station. The two signals can actually cause each other to cancel out) when that happens.
Check to see if your router has its little 'pigtail' sticking out at right angles to where your computer is located.
The pigtails on both should be parallel/in line with each other as pictured.
The tower shouldn't be sitting between the two (because the metal case blocks direct signal and you'll only receive reflection signal from other objects in the periphery.
Finally ........ if you double-click the D-link icon in the bottom right corner of the screen, you'll get a bar graph showing. Walk around while you view that bar and see if it shifts strength considerably. Shifting is caused by your OWN BODY reflecting signal!~
Microwaves and cell phone can cause enough radio interference to make the bar graph change considerably. While that's a misrepresentation of actual strength ..... it seems that D-link translates it that way. When other radio frequencies interfere, they create "noise" ..... which then causes transmission to be interrupted constantly so that the two have to keep re-sending the same packets over and over (slowing down the speed). My own graph slipped down to 40% when I ran the microwave. Otherwise it usually averages out at about 70%.
I suspect your little pig tail antennas aren't lined up with each other and/or you have a large metal box of some kind (fridge?) between the two.