I haven't been able to access the internet via a usb broadband modem ever since I installed windows xp pack 2. Every time I try to connect it displays error 797. I have tried uninstalling and installing the drivers without success. Any help please? Thanks!

Is it possible they made new drivers for the SP2 version of XP? Why don't you check the manufacturers site for your modem. If your not sure of the model (usually on the device itself) you can use an info tool like SIW (free) or Everest (as a trial version) to see the info of your PC's hardware. Get the latest drivers, uninstall the ones giving you problems before reinstalling the new. If that doesn't do it, uninstall the new drivers and reboot into safe mode and restore the PC to pre SP2.