You can search for Sellers via the Advanced link to the right of the eBay Search window. Scroll down to the Seller section and enter the ID and complete the Search at the top or bottom of the page.

If the listing is current and indexed, you can search by item number by entering the number directly into the search bar. Just paste your own item number of those digits at the end of the page address. That will work even if the listing has ended within ninety days or if it is not yet indexed.

If you can't sign in to your eBay account Make sure Caps Lock isn't on. Look for spelling errors. If you recently changed your username or password, your browser might remember your old information. Try manually entering your new username and password.