Unable to Access Secure Websites with Computers running Windows XP

Whoever can figure this problem out will be a genius. I have a home network
that includes: 2 desktop computers both running on Windows XP and 1 laptop
running Windows Vista. The desktop computers running Windows XP are unable to
go into secure websites, for example, microsoft update, banking bill pay or
almost anything that requires you to enter a passcode. We are having to use
my laptop running Windows Vista to access these websites. We have disabled
every possible firewall on these computers. We have followed all instructions
given to make the sites we are going to "Trusted Sites", We have had our ISP
come out to check out their hardware with no prevail. We have replaced the
router. Don't know what to do know. The funny thing about it is that it only
affects Window XP and Microsoft XBOX going online. When we log in using the
Playstation 3 to go online we have no problems.

Please help