Hi i think i got this tip from pixalo but cant remember

anyway i cant get it to work

. Can someone tell me how i get my pictures to have a complete white background. I have tried the method below but it just ruins the actual image of my boy and makes him look well over exposed and i just cant fathom it out. I have used a large white sheet as a background and i have a interfit studio kit and need some advice please. The method below did not work at all for me so any other method i would be willing to try. Thank you pixalo people
This is a lovely little technique for getting those white backgrounds in Photoshop CS+ (PS).
Take your subjects in normal light against a white backdrop. For this instance, I have three dining chairs on a sofa in the conservatory with a white duvet hanging off them!!
Open your image in PS.
Layer --> Duplicate Layer. Click Ok.
Layer --> Blending Options--> Change from Normal to Screen. Click Ok. You now have a white image.
Layer --> Duplicate Layer. Click Ok. Even whiter.
Layer --> Blending Options--> Change from Screen to Overlay. Now the image is really strange
Change the opacity until you are happy with the image. Click on okay.
Now to get a really white background, click on Layer --> New Adjustment Layer --> Levels
In the histogram, drag the white arrow to the right, left a little. Watch your image.
Also drag the middle arrow for the subjects a little until you are happen.
Click on Ok.
Now click on Layer and flatten image.
Okay, so you have your piccy. You can now alter the curves, saturation, and convert to B&W if you wish.
Check for any white areas that need touching up to make it perfectly white after you've finished.
Then, if you wish, click on Canvas size and add 1cm all around the image giving a clean white border.