Internet problems on my pc, but not laptops

[xnikx]

Ok so lately my pc has been shitty with the internet.

I use a wireless adapter but usually i can play with no lag at all.
But now while playing black ops ill lose connection to servers, minimize and see that my internet has dropped from 5 bars to 3 or 4.

I have comcast high speed cable, and linkseys router.

I took a speedtest

PC
Download 1.55mbs
Upload 2.64mbs
Ping 30mb

Laptop
Download 7.13mbs
Upload 2.62mbs
Ping 38ms

Any ideas to why my internet is dropping on my pc but not laptops?
It seems like the adapter but ive only been having problems recently.