I was given Wi-Fi adapter. I have an Internet through DSL. Could I use that adapter to spread Wi-Fi through usb slot of PC.

 

Are you asking if you could use the Wi-Fi adapter as a wireless access point?

If so, I found this, which may help.

 

I could not follow the instructions in this web, though I find some information and set up my adaptor , but devices do not work.

 

This video helps me to create Wi-Fi access point. It's very useful, I think http://www.youtube.com/watch?v=AguNyAdd6_Y