Something is very wrong. Perhaps some more information of what you are doing might help.
Otherwise, the only advice I can give is :
- Try to fully patch Windows by using Windows Update, including all
optional updates (except bing)
- See if Device Manage has an entry for Modems; if yes, delete it and reboot
- Find out your network adapter manufacture and search for firmware update
- Update the firmware of your router
- Check system integrity via sfc /scannow
If nothing works, the next step is a Repair Install
to fix Windows while preserving your user accounts, data, programs, and system drivers.