Outlook Express has gone belly up...

I've done something really stupid. I'm not exactly sure what but after downloading and installing a virus checker (Avast!4.6) and following some setup instructions about redirecting away from my ISP pop3 and smtp server to get transparent -on the fly- checking of emails, I now find that when I attempt to run Outlook Express I get the error message " Outlook Express could not be started because MSOE.dll could not be initialised. Outlook express may not be installed correctly " When I cancel that message another message immediately pops up "Outlook express could not be started. The application was unable to create the internet account manager. "I used Add/remove programs in control panel to uninstall outlook express and then re-installed it again. But it still didn't work. Same error and I noticed that the address book in the directory was the same old address book.I uninstalled it again and even deleted the Outlook express directory.This time I reinstalled the operating system (WIN 98SE) over the top of the current installation. Now I don't get a desktop icon for Outlook Express nor is there a mail tab in internet explorer. Obviously there is something very wrong with the installation. The old address book has somehow managed to find its way back into the outlook express directory. My question is simply in the WIN 98SE operating system how do I A) uninstall outlook express, completely :( re-insatall a fresh clean version of outlook express. ( hopefully retaining all the files and settings I have for win 98SE)Any help really appreciated. If all else fails it looks like a new (bigger) hard drive and complete re-installation of the operating system.I appologise for the lengthy post. Cheers,Roger