Did you try these steps? I tried every possible thing before I found this, and this worked. Posted earlier in this string.

Step 1

(This will Suppress the Desktop While Starting QuickBooks)

Press and hold the Ctrl key.
Double click your QuickBooks program icon.
Hold the Ctrl key until QuickBooks starts and displays the No Company Open window.

Step 2

(This will Suppress the Desktop While Opening a Company File)

Click your company data file in the No Company Open Window.
Press and hold the Alt key.
Click the Open button.
Hold the Alt key until the log in window appears.
Release the Alt key.
Enter your user name and password. (<< this is where I logged in as "admin")
Press and hold the Alt key.
Click OK and hold the Alt key until your file is completely open. QuickBooks will display a blank desktop.