Can't open attachments (forwarded email) in Outlook Exp. 6

Someone please help me 'cause I'm losin' it here! I can no longer open email attachments in Outlook Express 6. Here's the thing. I moved from home and computer to new home and new computer. I had 100's of saved emails stored from the previous Outlook Express 6. The new computer has Windows 2000 SP4. A relative decided to put it all together for me. He downloaded Internet Explorer and Outlook Express 6 for me, and then I Imported all those 100's of emails from storage devices to Outlook and got the new email address set up and running. Everything worked fine. Then the same relativce came along and decided to "upgrade" me without asking me. He added Foxfire and Thunderbird and imported my emails from Outlook Exp. to Thunderbird too! This for me turned into nothing more then added work and more nuisance than I wanted. Thunderbird as far as I am concerned is just useless wretched excess. I tried to import the emails back into Outlook Express with no luck. Then another relative (who does computer maintenance for a living) came and had to download Netscape Navigator to get my emails out of Thunderbird, into Navigator, and then imported into Outlook Express. I ended up with duplicates and triplicates of each email, but I got them back where I wanted them, and everything started moving along fine. Then I removed thunderbird and Navigator. The next thing I know, I start receiving my usual many emails each day that were "forwarded" to me. Then I realized I couldn't open any of them. Then I found out that any "forwarded" emails that I had saved from before also couldn't be opened. I kept getting the message that Windows couldn't find "thunde~.exe" or something like that. I tried everything and asked everyone. Finally I resorted to re-installing Thunderbird. This did not work at all. I got rid of Thunderbird again. Then, when trying to open email attachments (only when they are "forwarded") I was getting a message that I needed something that looked like ".eml" (but I can't remember exactly.) Lately I don't even get an error message of any sort. Trying to open these attachments at best makes a sound that I have associated with closing a program or minimizing a window. Still nothing opens. Can anyone tell me what I can do to fix this situation? I can open attachments that are videos or files that are sent directly to me, but not anything in an email that is "forwarded" and they are piling up on me by the trillions! LOL Please help! Thanks, Jimmy