How do I change my browser setting from IE 6.0 to IE 7.0? I get error messages when I try to attach

I installed IE 7.0. Today I tried to attach a file to my email and received this message, "Invalid file specified. Please try again." I did everything the same way as before. This is the first time I've seen this error message. Any suggestions?

How do I change my browser setting from IE 6.0 to IE 7.0? I get error messages when I try to attach a file.?windows xp themes

no clue