<p>OK, here goes:</p>
<p> </p>
Uninstall normally.
Delete everything inside C:\program data\openlp.org (I assume as you've done this before, you already backed up anything you need)
Whilst in C:\program data\openlp.org folder in Explorer, see if you have a "Compatibility files" option on Explorers toolbar. If so, click it and delete contents if any.
Install openlp again, a "Full" install. Is there a reason why you're running such an old version? Might be an idea to upgrade to a more recent one.
Do NOT restore any of your backed up files, if you were planning to do so. We'll worry about this later.
Start it up, ignore any errors. Go into the options, set the monitor and set use global themes, select a theme. Close dialog.
Exit openlp, and start it again. Do you get an error now?
<p> </p>
<p>Do you have a backup of your song database you need to restore? If so, did any songs have their own theme? We'll need to do it a bit of maintenance on it to remove links to your themes, that you shouldn't have deleted.</p>
<p> </p>