Hi, I'm John! I will help you with this.
To help narrow down the issue:
- Is the keyboard wired USB, wireless USB, or Bluetooth?
- Does the keyboard light up or respond before Windows loads, such as in the Dell startup screen or BIOS?
- Did the internet outage also include a power outage or sudden shutdown?
The internet outage itself should not normally stop Windows from detecting a keyboard. It may be a USB, Bluetooth, driver, or power issue that happened after the restart.
First, please try these basic checks:
- Unplug the keyboard and plug it into a different USB port, preferably one at the back of the Dell PC.
- If it is a wireless keyboard, replace or recharge the batteries, then reconnect the USB receiver or re-pair the keyboard.
- Restart the PC again with the keyboard already connected.
- If you are stuck at the sign-in screen, click the accessibility icon and use the On-Screen Keyboard temporarily.
If the issue persists, please provide more details by answering my questions.
Thanks!