That's a much older machine with very limited hardware resources, Scott.
First, you should have at least 4 gigs of RAM. 1.5 gigs is barely enough for Windows to run!
But this is compounded by the fact that you've only got 38 gigs of free space on your hard drive. You may be able to get the program running again if you do a Disk Clean-up and a Defragmentation. But those 38 gigs are going to fill up awful quick with media files. And once you get down below 30-20 gigs of free space, the program doesn't have room to operate.
Unless you're able to either clear off 60-70 gigs of space (and clean and defragment) and/or add a second drive for your video projects, it's likely the program is not going to be able to run.
I agree with Steve's accessment of potential problems.
Along with those, this article, http://forums.adobe.com/thread/792580 might be useful in getting PrE running. It starts with a checklist to set up PrE, then goes into steps to tune up the computer and the OS, then offers links on troubleshooting.
As PrE did run (that may well have been before the HDD became so filled?), I would also set a System Restore Point for today (in case this does not help), and then boot to Safe Mode. From there, choose a System Restore Point, before you upgraded WMP. Let the system reboot, and test. If that does not help, you have only lost a few moments, since you did create the System Restore Point for today, and can go back to it.
Thanks for the info. My 40 GB HDD and 1.5 GB RAM were enough to launch the app at first. It crashed a few times (possibly due to limited resources), but I was able to use it.
If resource limitations are an issue, shouldn't the app report it, instead of a silent failure? Or is there a log file somewhere? That seems like it would warrant either a bug report or a feature request for the next version.
My C drive is only 70 GB to begin with. I freed up 6 GB by moving that data to my external USB HDD. I really doubt I can free up much more. But those extra 6GB didn't affect anything. In fact, when I try to open my project from the Welcome window, taskmgr shows the CPU usage "peak" at 14% and then go back to <5%. So whatever happens, it gives up quickly.
BTW, I know I should get another internal HDD -- I'm not discounting your point. And more RAM couldn't hurt either!