ThorConnWndClass is a method (entry point) defined in inetcomm.dll.
Maybe your copy under %windir%\system32 is corrupted or been replaced
with malware, or malware, you, or a registry cleaner (which comes back
to you as the authorizing agent for any proposed changes) removed the
registry entry for the reference to this method in this DLL. First see
if reregistering the DLL fixes the problem:
cd %windir%\system32
regsvr32 inetcomm.dll
If that didn't work, check the copies of the file exactly the same
under:
%windir%\system32\inetcomm.dll
%windir%\system32\dllcache\inetcomm.dll
You may need to use a DOS prompt to get to the DLLcache folder since
Explorer will hide it (even if the option to display hidden files is
enabled as it is considered a special folder). Use the 'fc' DOS program
at a DOS prompt to compare the 2 files ("fc /b <file1> <file2>"). If
they are not the same, copy the one from the DLLcache folder, or run
"sfc /scannow". If the copy under the DLLcache folder is also bad, you
need to delete it and rerun "sfc /scannow" but that will require your
install CD or an i386 folder from which to retrieve a good copy of this
file.
Of course, if malware is the cause then you need to start scanning for
malware using multiple anti-malware products. None of the anti-malware
products have great coverage and overlapping them improves coverage
