SNMP returns incorrect values on Windows system after resizi

Hello. I use MSP to monitor lots of Windows systems. We have noticed that on certain systems we have had to use disk partition tools to resize the boot partition on a system, and from that point forward, SNMP values are incorrect. Is there a place in the Windows registry where I can change values? 1.3.6.1.2.1.25.2.3.1.6 is the value that allows the great disk usage chart to appear on the snapshot page and that happens to be the problem oid. It is reporting 100% used all the time.

Also, is there a way of using Partition Details of the Device (%) counter to monitor just C and D for example, but not monitor Virtual Memory or Physical Memory. I believe in a previous version of OpManager I could but cannot see how to exclude those others in new MSP.

Thanks in advance!