OK here's a way that should work no matter how your desktop is set up....
Go to the command prompt and enter the following three commands pressing return after each one
c:
cd /
dir outlook.exe /s
The third command will take a while, it should come back with something looking like...
C:\Program Files>dir outlook.exe /s
Volume in drive C has no label.
Volume Serial Number is E095-B5AC
Directory of C:\Program Files\Microsoft Office\Office12
17/08/2009 23:54 12,957,536 OUTLOOK.EXE
1 File(s) 12,957,536 bytes
It's the Directory part that you're interested in.....
When you can type into the window again enter the following
\Outlook.exe
So as said I would enter:
C:\Program Files\Microsoft Office\Office12\Outlook.exe
Does Outlook try to open?