Hardware Troubleshooting: Cold Booting Versus Warm Booting

• Microsoft MS-DOS operating system versions 6.0, 6.2, 6.21
• Microsoft Windows operating system versions 3.0, 3.0a, 3.1, 3.11
• Microsoft Windows for Workgroups versions 3.1, 3.11

SUMMARY

When troubleshooting hardware issues, using the power on/off switch yields the most consistent testing procedure. If you suspect a hardware problem, particularly an adapter card problem, using the power switch, rather than the CTRL+ALT+DEL key combination or the Reset button, is recommended.

MORE INFORMATION

A warm boot, accomplished by pressing the CTRL+ALT+DEL key combination, restarts the computer through the INT19h ROM BIOS routine. This warm-boot procedure usually does not go through the complete boot process; generally, it skips the power-on self test (POST) to save time. In addition, a warm boot frequently fails to reset all adapters in the computer's adapter slots.

If you use the Reset button to cold boot the computer, it generally restarts the boot process, including the POST. However, this procedure does not necessarily discontinue power to the motherboard. If the power is not interrupted, the cold boot may fail to reset all adapters in the computer's adapter slots.

To ensure that all adapters are properly reset, you should use the power switch to turn the computer off. Leaving the power off for ten seconds ensures that all the capacitors on the motherboard have time to discharge and should also give the hard disk drive a chance to stop spinning.

NOTE: Using other reboot methods, such as CTRL+ALT+DEL or the Reset button, is acceptable when a hardware problem is not suspected.

If you are using a write-behind cache, ensure the contents of the cache have been written to the disk before using the power on/off switch. When using SMARTDRV.EXE version 4.0 or later, typing "smartdrv /c" (without the quotation marks) accomplishes this.