There's a problem with Photoshop CS when you install the 1700 plugins pack. You may find the program locks up or gives you a missing .dll message.
Just go to start/find/ and search for Msvcrt10.dll
when it's located, copy and paste it into the Photoshop CS folder in Program Files.
Restart Photoshop and it should work OK.
If you don't have it, I can supply a link for the download.
There may be a few other .dll's required depending on your installed software.
It's not a serious bug, just a compatibility issue.