When asking a question on the Photoshop user-to-user forums, you can make it easier for folks to help you by proactively providing the answers to the following questions:
- What version of Photoshop? Include the minor version number (e.g., Photoshop CS5 with the 12.0.4 update).
- Have you installed the recent updates? (If not, you should. They fix a lot of problems.)
- What operating system? This should include specific minor version numbers, like "Mac OSX v10.6.8"---not just "Mac".
- What kind(s) of image file(s)? When talking about camera raw files, include the model of camera.
- If you are getting error message(s), what is the full text of the error message(s)?
- What were you doing when the problem occurred?
- Has this ever worked before?
- What other software are you running?
- Tell us about your computer hardware. How much RAM is installed? How much free space is on your system (C:) drive?
- Has this ever worked before? If so, do you recall any changes you made to Photoshop, such as adding Plug-ins, brushes, etc.? Did you make any changes to your system, such as updating hardware, printers or drivers; or installing/uninstalling any programs?
Screenshots and sample movies are often very useful in showing exactly what you're seeing, and can thus make getting an answer faster and easier. FAQ: How do I capture and post a screen shot or video?
Also, please do everyone a favor and check the Photoshop FAQ list and also do a quick Photoshop Community Help search to see if your question has been addressed already.