Heres the deal and some background info.
Issue: Non Administrators cannot log onto 3 different servers on console, or through RDP. The servers are Windows 2003 Standard, and one is Enterprise. 2 of them act as File/Print servers, the other is an Exchange Server.
Cause: All these systems exhibited this behavior after installing Paragon Disk Manager in order to resize the drives to facilitate extra space requirements that we allocated on our SAN.
Basically, after we narrowed it down that the applcation has messed up something with the server, we placed a support call. After investigation, Paragon advised us they were extremely sorry for what their application has done, but have no means of resolving the issue.
So...Ive tried adding users that are generally in the Power Users group to the Admin group, and bam, they are able to login. If they are only members of the Power Users group, they get an error saying "the application failed to initialize properly 0xc0150002" and references explorer.exe. I've tried resetting permissions on the C drive to allow full control, and but hasnt worked. Another interesting note is that on the File/Print Servers is that they are no longer able to utilize advanced printing features, so we had to disable this on printers. I believe the issue is related to something in the registry that may be turned off, or something with Local Policies, however a gpresult does not show anything of this nature. My next step is to reinstall SP1 on 2003, or just move to SP2. Still though, this worked before this application was installed, and I just cant fathom what it may have changes.
Thanks for the help in advance.