Vista Ultimate 64 hangs when I attempt to upload a file to hotmail

Hi,

I have a new PC with Vista Ultimate 64. I have had no problems with it so
far until today when I attempted to send an email to a friend.

To replicate this issue I simply sign onto my Windows Live Hotmail account.
Click the new button. Click Attach, File. Browse to a file select a 400k
Jpeg image and click Ok.

The image starts to upload. After a few seconds the screen freezes, and
Windows becomes completely non-responsive. It will not respond to anything I
do including pressing Ctl-Alt-Del. The only way to extricate the computer
from this situation that I have found is to hit the restart button.

Does anyone have any idea about the best way of troubleshooting this issue?

Thanks.