My Premiere CS5 has been running fine since I installed. But today no matter what I do, when I try to open the application it appears to try to launch (never does) then process abruptly ends when viewing in Windows Task Manager. I deleted some auto-save projects to no prevail...any thoughts? I appear to have plenty of hard drive space and memory (I can open PS and AE at the same time)
Harm has given you a great place to start, as that info will help us remotely troubleshoot for you.
Now, when something works one day, but not the next, then something has changed. The challenge is to figure out what has changed.
It could be something as simple as an OS update/hot-fix rendering your video driver obsolete. Update that, plus your audio driver too, just to be safe.
It could be the addition of other software, or hardware. Have you added ANYTHING?
If you have added any audio-editors, or VST's for existing editors, it could be the VST's getting in the way. Rather than go into a bunch of details, I'll wait until you finish with Harm's suggestions.
When I get a change, my first action will be: create a new System Restore Point (for now - today), and then boot into Safe Mode, choosing a Restore Point, back when things DID work. Test.