I have recently installed the free TeXnicCenter IDE for working with LaTeX documents. It is a nice frontend. However, getting it to produce PDFs and preview them in Adobe Reader 10 wasn't a breeze. I easily found help on how to configure it to produce PDF documents on some forums (google around, if you're stuck at that stage). But the preview was broken. I would get failure when the DDE command was run. Adobe Reader would open but sit at it's main splash screen.
I opened Adobe Reader's preferences (ctrl+K) and set the "Show splash screen" (not sure if that one helped), and unchecked "Enable protected mode on startup" on the "General" tab. That solved the problem.
6 months ago