EBAY SIGN-IN U/S

I used Ebay to buy machinery, until the laptop died. The new Dell Dimension on the same router has never suceeded in connecting: it returns to the sign-in or Guest page and clears the password.  If I put an incorrect password in, an error "invalid information " is displayed, but no error if correct words.... just stops on "sign in please". Ebay have replied, but not solved it. Dell are useless so far, just hours on the switchboard, no e-mail reply.

 

I use McCaffee privacy and firewall, no XPsp2 firewall, IE6, overrride auto cookie handling accept session and other cookies, SSL3 SSL3,

 

WHAT SHOULD i TRY???