I can't sign in to ebay from my main computer; I can get to the main ebay website (www.ebay.com) and I can get to sign-in page, but when I enter my user ID and password, ebay displays an error page and returns immediately to the sign-in page. The error page flashes by so quickly I can't read it, although I have tried probably 30 times or so to catch enough of the words to determine at least the subject of the problem. I've cleaned out the cache, including all cookies; I've added several ebay pages to trusted sites, I've tried it with security levels set on lowest setting, and checked everything I know and still no results. I've also contacted ebay and done everything they suggested (which was actually very little), still with no success. Ebay is not listed as a blocked site.
We have a laptop which accesses from our home WIFI network, and on it I am able to sign in just fine. Also, with Mozilla Firefox I am able to sign in just fine. So there is some small setting on my main computer that is preventing me from signing in. I've searched all of the Tools - Internet Options tabs and settings, and can't find out what may be preventing my access. Pop-up blockers are off, both in IE9, Google, etc.
Every other website I've visited since this began happening works fine. The problem began when I downloaded the latest updates from Windows Update about 3 or 4 days ago. My IE9 is completely up to date, I use Windows 7 and ESET security software. Nothing has changed in my software or in how I access ebay except for the latest Windows updates. Please advise; thank you.