Windows 7 - Copying a link opens that link up

Erm, I figure this counts as browser help, but if it's not, mods can feel free to move this...

So, it's just as the title says. At first, I thought the problem was very specific. If I copied a link via <CTRL><C> and <ALT><TAB>'d to a different window (generally an IM) window, I noticed the link would open up in Chrome (my default browser). I figured it was an extension causing this problem.

The next day, though, I noticed this just happened if I copied a link in general. About a second's delay after copying the link, the copied link would open up in a new tab. I figured this was entirely in Chrome still, so it must be a problem with Chrome. I updated my version of Chrome to the latest and went through all my extensions to see if one of them was causing trouble. This wasn't the answer.

Later, I copied a link from a friend in Pidgin... and the link opened itself in Chrome. This was not a problem stemming from my browser, it seems, though still obviously a problem involving it.

I've already run a full system virus scan (I use Avira, if that's important to know) and come up with nothing. I've Googled this problem and can't find anyone with a similar issue. I just... what could this be?