In This post i am explain about Raining Effect in Photoshop it is very easy to create , Just Follow the steps you can easily understand this effect, I think it won't work in Photoshop 7 because u don't have some option in that , Try it in Photoshop cs5. The final result is looks like the above image.
Step1: Open the new Image
Step2: Right click the Background image create duplicate layer
Step3:Create New Layer
Step4: Choose paint bucket and Choose black color
Step5: Fill Black color in new layer
Step6: Go to Filter->Render in that Fibers
Step7: Fix Variance 64 and strength 4
Step8: Fill the layer 26% like below diagram.
Step9: Go to Blur->Motion Blur
Step10: Fix angle 63 Degree and distance 43 pixels
Step11: Fill the same layer 39% Now see the result