First thing is to reinstall CR runtime (like stated in message above) (disable all anitivrus software!). If this doesn't help (and CR won't run even at admin user account), then I would use Mark Russinovich Process Monitor to find out, what key or component can't be accessed/loaded. Of course you should look at windows events - maybe there are some meaningful messages there.
Arvo
2009-07-11 14:16:19