Help with PC needed

To cut a longish story short, last Thursday night I had to reboot / recover my nice new shiny PC. Since then it wont allow me to go online. I have uninstalled and then reinstalled my broadband software and router, but it still wont allow me on.
A message appears in an Error box saying…… Cant get registry value for Blah blah blah (my router system)
Everythin else reloads fine. I can even play my ps2 online so I know its not the router and that the broadband is still connected.
I have phoned PC World (i hold my head in shame from going there) and they tell me that because I hadnt purchased the extended warrenty that my software is not covered….. but I have only had the PC a month.

Can anybody help me please…I can only come online whilst at work