First, is your desktop having all its drivers installed? If you did a format you likely lost all drivers that were not included in your OS distribution package. Go Control Panel - System - Devices - Device Manager and check for exclamation marks anywhere. Then decide what you need by e.g. checking the manufacture's website.
2nd Q:
Is you combine ADSL and analogue devices on a single phone line, all analogue devices must be installed behind an ADSL filter box or filter plug, otherwise neither class of devices will work properly.