try to find out if there is a add-on that is preventing to start
IE in normal mode.
1. disable all the (especially the non verified) add-ons restart IE and test it.
if this works now fine, then you shoud now try to find out
one by one till you get the one which is preventing to start IE in
normal mode. you should uninstall this add-on with the same
software that installed this add on.
2. or your computer might be infected, do a spyware/virusscan.
3. if this not works : you may want to try doing a system
restore to a time when you could use the IE while not in safe mode
Good luck and let me know if my help was useful ;-)