@MHooper
There is a clean uninstall procedure you can do to ensure that all previous files of LoadRunner are not in your system. Please follow the below steps:

1. Make sure that all running LoadRunner processes (including the Controller, VuGen, Analysis and theLoadRunner Agent Process/Service) are not running.

2. Back up any existing scripts that may have been saved in the LoadRunner installation folder. (The scripts are sometimes saved in a ''scripts'' subdirectory under the LoadRunner installation folder.)

3. Run the uninstall program from the LoadRunner / Service Test program group (or) use the Windows Add/Remove Programs from the Control Panel. If any prompt is given about removing shared files, remove all the shared DLLs that are reported as they are no longer in use. In the very rare instance this causes a problem for some other application it may be necessary to reinstall that other application. This is not generally a problem because every application should have registered which DLLs it needs to run.

Command Line unistall: msiexec.exe /qn /uninstall ''lrunnerLoadRunner.msi''

4. Reboot the machine after the Uninstall wizard is complete. This will complete the basic uninstall procedure.

5. Delete all LoadRunner folders (including the ones in the Startup menu for theAgent Process).

6. Do a search for the following files and remove them from all locations -- they will be replaced during the reinstall.
a. wlrun.*
b. vugen.*

7. Open the registry editor (Start > Run > regedit).

8. If they exist you can delete the following keys:
HKEY_CURRENT_USER ->Software -> Mercury Interactive -> LoadRunner - see Note below
HKEY_CURRENT_USERSoftwareC:

9. Empty the Recycle Bin.

10. Now install LoadRunner according to the installer guide included with the install media.

Note:You may want tokeep thecell HKEY_CURRENT_USER -> Software -> Mercury Interactive -> LoadRunner -> License if you do not have a copy of the existing LoadRunner license.This note does not apply if the machine will be used for LoadRunner 11.50 as a new license will be required in this case.

If you follow all of the steps above and you are still getting the same message Microsoft has an uninstall tool that can assist as well.

http://support.microsoft.com/kb/290301/en-us