So, the Poser support people responded to my inability to get Poser 11 to work in spite of clean installs with the following:

"Poser's library window is really just an embedded Chromium web browser. If the library window is crashing it would only take out Chromium and not crash Poser it's self. That situation can cause a blank library window.

If you've removed all the preferences, included base content and reinstalled that leaves us with something in Windows has got messed up and is preventing Poser from running. Sometimes Windows tries to be helpful and changes registry settings for Poser that it really shouldn't. 

If you don't know exactly what you're doing don't mess with the registry. You can easily break Windows. If you're not 100% comfortable in RegEdit use a commercial registry cleaner. Backup everything before you try any of this. You don't need to uninstall poser to try the registry fixes.

Registry entries on Windows that may cause problems:

Background Activity Moderator (BAM). Seems to cause Poser to run as only an idle task. Cause massive performance hit. Search the following key for instances of Poser, FFrender and Queue executable. Delete all references. This will grow back. There's no way to stop Windows from helping.

Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\bam\State\UserSettings\S-1-5-21-3029514950-4203302119-1443304429-1001

Fault Tolerant Heap (FTH). Seems to get triggered after a crash. Causes very slow performance. Search for Poser executables in this key:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers

You can stop Windows from ever doing this again (and probably should). FTH can be disabled in this key:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\FTH\Enabled

Set enabled key to 0 (zero)"

Can anyone help me decipher this?  I'm really nervous about messing with the Windows registry.