There's nothing in IE7 Beta2 which would make it "crash all the time." I
suggest that you got infected with hijackware around the same time you
installed IE7 Beta2. Returning to IE6 or even repairing/reinstalling it
won't help: Hijackware infects Windows, not IE.
Checking for/Help with Hijackware
http://aumha.org/a/parasite.htm
http://aumha.org/a/quickfix.htm
http://aumha.net/viewtopic.php?t=5878
http://wiki.castlecops.com/Malware_Removal_and_Prevention:_Introduction
http://mvps.org/winhelp2002/unwanted.htm
http://inetexplorer.mvps.org/data/prevention.htm
http://inetexplorer.mvps.org/tshoot.html
http://www.mvps.org/sramesh2k/Malware_Defence.htm
http://defendingyourmachine.blogspot.com/
http://www.elephantboycomputers.com/page2.html#Removing_Malware
When all else fails, HijackThis v1.99.1
(http://aumha.net/downloads/hijackthis.zip) is the preferred tool to use.
It will help you to both identify and remove any hijackware/spyware. **Post
your log to http://aumha.net/viewforum.php?f=30,
http://castlecops.com/forum67.html,
http://forums.subratam.org/index.php?showforum=7, or other appropriate
forums for expert analysis, not here.**
--
~Robear Dyer (PA Bear)
MS MVP-Windows (IE/OE, Shell/User, Security), Aumha.org VSOP, DTS-L.org