Right people ill try go tru this in abit more detail!
1, Switch on PS3 and laptop/desktop and connect the two with your Ethernet network cable (cat 6 if possible)
2, click START and enter CONTROL PANEL on laptop, then select NETWORK AND INTERNET CONNECTIONS, then NETWORK SETUP WIZARD, click next tru the first two pages, on the 3rd click IGNORE DISCONNECTED NETWORK HARDWARE, on the 4th page click THIS COMPUTER CONNECTS DIRECTLY TO THE INTERNET option, 5th page select whatever internet connection you use, 6th page select the ETHERNET option, then keep clicking next until it runs the setup. once its finished it should give you a few options, pick the option that says FINISH
3, On ps3 select NETWORK SETTINGS on the main menu, then INTERNET CONNECTION SETTINGS, select EASY method, then WIRED CONNECTION, after that just keep flicking right until your asked to run connect test.
When the test runs it should find the ip address, If it find it ok there should be no reason why it wouldnt find internet connection or playstation network. If you have any trouble redo step 2, when it finishes, run the internet connection test on its own on ps3. You might have to try it a few times if its still givesyou problems.
The only problem with this is if the PS3 freezes or ur signed out for no reason ul have to run step 2 again and do a connection test. It can get annoying at times.
I dont use this setup myself anymore! I found a 3g usb router from dovodo. The great thing about this is you dont get connection faults that often and if you do its only a matter of signing in again. Plus I have wifi everywhere in the house!
I hope this helps, If your still having trouble maybe look into getting a router!