Computer becomes extremely frame-y and slow when downloading torrents.

[ShakeSoda]

A little back-story first.

Before I was having these problems with µTorrent, my machine was working flawlessly. I could surf the web, play videos, listen to music, use µTorrent, etc. all at the same time.

Then my internet stopped working. Long story short, the internet was cut off due to circumstances beyond my control. After about a week, I finally get my internet back. I can perform all of the activities stated above just fine, but as soon as I start up µTorrent and start to download something, my computer gets all frame-y, and slows down the music I'm listening to, the video I'm watching, what I'm doing on the internet...

Any suggestions please?

-Shake