Can’t open attachments in email.

My pc operates with Windows 98-Second Edition. I use Outlook Express 6 for email. For days now I cannot open any attachments. I click on the paperclip, tried double-clicks. Nothing. The title comes up “grayed” like it is open already. Doesn’t matter if the title ends with .eml, .url, .jpg,.url, .jpeg, .doc, etc. — none of them open. Recently I noticed a message at the top of one email that says “OE removed access to the following unsafe attachments in your mail” and the address was given. I have no viruses. I called the tech support for my computer and they had me reinstall windows, but the problem continues: I can’t open any attachments!! Any suggestions or help would be appreciated. Thanks in advance!