What extensions do the files have that won't open? (.jpg - .pps for instance).
Are you using Outlook Express for e-mail? If so, doing a repair job on Internet Explorer and Outlook Express might be the answer. I'm not sure of the procedure for that with Windows 2000. Repairing them in XP involves using the installation disk. Maybe W.2000 is the same.
As Igorian suspects, it could be that some malware has found its way onto your computer. I think that needs checking out, just in case. To see if your system is clean, it might be best to update your antivirus definitions and do a full system scan. Do you have Ad-Aware and Spybot installed? If so, update them and scan the system. Even when they are freshly installed, they need to be updated before use.
I think you'll need to fix anything the anti-spyware programs find and see how things go. They make back-ups before deleting anything, so if something does get taken out that's needed, it can always be put back in again.
It might not be anything to do with all that but running these programs once in a while is a good thing to do anyway.
Another option would be to install and set up another e-mail program. Being a Mozilla fan, I'm bound to recommend Thunderbird
. It's a good alternative to OE.
Ad-Aware:
http://tinyurl.com/yu6cm
Spybot S&D:
http://tinyurl.com/37t9f
Thunderbird e-mail:
http://tinyurl.com/2b85n
