Appears to be a possible conflict with Windows Aero, at least it was on my workstation running CS3. I was finally able to get it to work by changing the following settings ....
Right-click on the Dreamweaver shortcut and select Properties.
Switch to the Compatability tab.
Under the Settings section, select 'Disable visual themes' and 'Disable desktop composition'. (It typically worked without disabling the visual themes, but another time it didn't so I just left it checked. I'm pretty sure all settings are restored when you close DReamwevaer anyway.)
Oh and I had compatibility mode set to Windows XP (SP2) and run as admin.
I guess you could disable Windows Aero altogether, or at least the Aero Peek feature, but I like both and really didn't want to see them go. This option gave me the best of both worlds. Guess this will all be a moot point when we finally get with the times and upgrade, but for now, hope this helps at least one person!
