My ADSL connection (using a NB1300 modem) drops out periodically when using the internet, and the same problem is experienced using the modem with my Xbox. The connection does not disconnect from the server, but it just stops uploading and downloading. There is no problem at the ISPs end, the phone line is fine and the modem is not setup to time-out. The computer is running Windows XP. The problem occurs regardless of which application is being used (e.g. Netscape, Firefox, or Outlook).

Since the problem occurs regardless of whether you are using the PC or Xbox, it is unlikely to be related to your computer, but there is instead a problem with the ADSL modem. Unfortunately, in my experience, network issues like the one we are trying to resolve are hard to fix even when sitting in front of the machine, so fixing them by correspondence is even more difficult. However, for situations like the one you are experiencing my first procedure is to perform a factory reset on the device and start a reconfiguration from scratch. However, make sure you know what settings you need to input into the device beforehand, in case you need to go into the router and check these settings before doing the reset. Apart from this there isn’t really that much I can suggest, except you could try contacting your ISP for guidance on the issue.