I agree Will, I believe it is something with your computer, I'm just at a loss as to what it could be. Are you using any plug-ins (Extensions) with your browsers? If so please list them.
You can not access Ebay using IE or Chrome
Ebay is the only site affected.
Your wife shares the same Internet connection with out any problems.
Computer at times hesitates. (this is why I thought about a root kit)
Have I left anything out Will? Another thought would be to un-install Chrome and reinstall it or install FF.