I recently received an e mail with an attachment, and it was not in the junk mail or notified as a spam. But when ever I tried to open the attachment, my computer got stucked and also the system did not support the way of rebooting in the proper way, which caused me to switch off the computer to restart. Why does this happen? The virus guard is also enable and up to date and does not show any significant active threats. What should I do to view the attachment?