Outlook Web Access--can't send

I use Outlook Express for my regular email, no problems, but I read my school e-mail at home via Outlook Web Access.

I use Windows XP, Office Prof XP, and IE 7, use MS auto update.

I have run Ccleaner, SpyBot, AusLogics Disk Defrag.

Since May 2007, on occasion, I have been unable to forward/send Outlook Web Access messages. I received them OK. When I want to forward, no message appears in the body of the new email, and two lines, instead of one, appear for to, cc, bcc. When I see the 2 lines, I know the message won't go. It sits in the drafts box. Last spring I was unable to send for about 1 month, then it worked OK, I don't know why. The problem has appeared on occasion since then, but disappears in a day or two or a week.

New problem: The not sending problem existed again this week. Yesterday I was nosing around again for a fix. I downloaded 924334 hotfix package from http://support.microsoft.com/?kbid=924334 but it would not finish installing--says Update for Exchange Server 2003 (KB911829) Setup... Invalid exchange server instatlation. I tried several times.

I also did the the S/MIME control in Options, e-mail security. Now, when I want to forward/send new, I only have a blue box, no to, cc, bcc. HELP!