A computer prompting for the date and time each time it boots is caused when the CMOS or RTC battery is bad or needs to be charged.

Charge the battery

Before replacing your battery, try leaving your computer on for two full days. In some cases, this can recharge the battery and prevent the issue from occurring.

Windows 95 and older computers

If you are running Microsoft Windows 95, Windows 3.x, or MS-DOS, verify that the computer has an autoexec.bat and config.sys file. If this file is missing, it needs to be recreated or restored from a backup.

Replace the battery

If you have a computer later than an 80286, the CMOS or RTC battery has died. You may contact your computer or motherboard manufacturer to purchase a replacement battery. Or, if you have a coin cell battery on your motherboard, you may also want to find a replacement online or through a local electronics store.

Older computers using an Intel 80286 and lower processor do not have a CMOS or RTC battery, which means the time and date must be set each time the computer starts.

  • How to replace the CMOS battery.
  • Computer motherboard companies and contact information.
  • Computer company contact information.
  • CMOS help and support.
  • MS-DOS and Windows command line help and support.