this sounds like you did an over the top installation, did you format the hard drive first?
you may also need to reinstall all the drivers for the devices in your machine, one easy way to check is to open device manager (start|control panel|switch to classic view (if needed)|system|hardware|device manager
and see what is plinged (has a yellow icon with an exclamation mark (|) next to it.
also try a btclick account, you only pay for the call (0845 number) and you do not have to supply a real id you can use anything (i.e. username: cheese password cheese) if you can connect via that then the problem is with the isp, and so you will need to contact them, or try a full clean install, but be aware tyhis will wipe off all the files on your pc, so a backup is advised.