Clearing Registry- MathCad 14 won't start

I use MathCad about once a month, and recently when I click the icon, nothing happens. I am running version 14 on Win 7. I don't recall any major changes to my computer in the intervening time other than installing some compilers.

I finally ran the MathCad remove feature from the install disk, and removed prior editions as well with the MS remove feature. (I have been using upgrades for about 15 years). I deleted any reference to MathCad/MathSoft from my program_files.

After reinstalling the product sucsessfully it still does not start. The only traces that I am aware of after the removal process were system registry keys. I usually avoid playing in this area but the temptation is to delete the regsitry keys for MathSoft and try to reinstall. Has anyone done this? Anything risky I should be aware of?

Thanks,

Fritz