error 1723. windows installer error. missing dll file

I am having trouble trying to install mathcad onto my windows 7 laptop. Everytime i run the installation i get an error 1723, windows installer error, missing dll file. I have exhausted all my knowledge of computers. I have even started going into the registry and trying to delete Java after reading some forums but with no joy. HKEY_LOCAL_MACHINE/Software/Microsoft/ Windows/CurrentVersion/Uninstall I do not know if i have managed to delete everything that I need to but deleted all the items that related to Java. I have uninstalled Java so many times, trying to install it offline and online. I have installed every update that i can for my laptop and still the error persists. I would appreciate any guidance on this issue.

ERROR 1723

This is a java incomplete un-install problem.

Follow the batch file fix in Apppleoddity's post here:
http://forums.whatthetech.com/index.php?showtopic=104537

Cheers,
Lee