Windows 7: Random lag spikes..?

For about the last week, I've been getting about 1 minute spikes of lag, where I can't load webpages, YouTube videos stop loading (or load REALLY slow, and continue to load slow) and such stuff. I haven't changed anything on my network, either.

My specs:


I use a wireless adapter which is a D-Link DWA-125 Wireless N 150 USB Adapter (Rev.A2).

I'd also like to add that, even when I'm not experiencing one of these spikes, youtube videos load REALLY slowly.