I use Gmail. It's very reliable, accessible anywhere there's a connection to the net and has huge storage capability. When you move to another country, state or province, nothing happens. Compare that to what happens if you rely on a POP3 mail account provided by a specific Internet Service Provider.
That said, it is possible to deal with a corrupted Outlook Express (which I happily do not use). If you open the control panel, click on Add/Remove programs, then click on Add/Remove Windows Components. If you uncheck Outlook Express, it's removed. Reboot, then reverse the procedure, putting the check mark back beside Outlook Express. This should fix OE. I'm uncertain what happens to existing mail messages in your inbox, outbox etc. YMMV.
In my mind, Outlook Express is so yesterday. FWIW, Microsoft is nuking OE in Windows Vista and will provide a new client called Microsoft Mail. I won't be using this program either. I will attempt to delay 'upgrading' to Vista from XP for as long as I can.