adobe reader 8.1 downloadingWhy cant i read any pdf files I have downloaded adobe reader 8.1.1 and acrobat professional 8 and it shuts me?

WHENEVER I TRY TO OPEN EITHER ADOBE READER 8.1.1 OR ACROBAT PROFESSIONAL 8 IT COMPLETELY SHUTS INTERNET EXPLORER DOWN. SO IF ANYONE CAN HELP ME PLEASE DO AS SOON AS POSSIBLE.
I have exactly the same problem. I used adobe reader 8.1 downloadingto have Adobe reader 5 and had no ploblems downloading pdf files. when ever I did I got a message to download the latest version....which I did. Now if I try to download a pdf it shuts my whole browser down....adobe reader 8.1 downloadingwith stupid error messages about checking my Adobe add ons...which I've done and there up to date....but to no avail...I'm stumped...would like to know what setting on my computer are screwed up...