Inorder to delete the other vista operating system installed on one of the partitions, we will have to format the partition,
see this link on how to format a partition using the Disk management console,http://windowshelp.microsoft.com/Windows/e...0129a71033.mspx
Assuming that you are keeping the older vista operating system that was previously installed, you will need to boot
from here in order to delete the newer one which got installed erroneously, or vice versa if formatting the older partition.
Sugguest you to back up the data in both the partitions to a safer place.
As for the Runtime C++ error, click on start -> type "appwiz.cpl" (without the quotes) and hit enter.
In the programs list look for Microsoft visual basic C++...If found Uninstall it.
Download a fresh copy of Microsoft visual basic C++ from here..http://www.microsoft.com/downloads/details...4d-389c36f85647
Read the system requirements mentioned in the above link carefully.
For clean instalation of vista go through this link...http://www.5starsupport.com/tutorial/vista-clean-install.htm
Hope this helps.