Troubleshooting Boot-Time Error Messages

The BIOS performs a power-on self-test (POST) when it starts up the system, to check out the PC and make sure that everything is working properly. Assuming that the BIOS is able to boot the system far enough to gain access to the video subsystem, it will display information about the PC as it boots. It will also use the video system to communicate error messages to the user. In fact, most boot problems are displayed via video error messages. 

An error message can be produced by various different parts of the system, depending on how far into the boot process the system gets before it is produced. Most error messages are produced by the system BIOS, as it is responsible for most of the functions of starting the boot. However, other error messages depend on the operating-system. 

There are many thousands of individual error messages; some are more common than others because there are only a few different BIOS companies that are used by the majority of PCs today. However, since the exact wording of an error message can be changed by the manufacturer of each system or
motherboard, there are a lot of variations.

In most cases, the messages are pretty similar to each other; Similar error messages, those that really mean the same thing but just use different wording, have their descriptions and diagnoses grouped together to make things simpler.

Some examples of error messages are:

1. BIOS ROM checksum error - system halted 
2. Cache memory bad, do not enable cache! 
3. CMOS battery (has) failed 
4. CMOS checksum error 
5. CMOS display type mismatch 
6. Disk boot failure 
7. Disk boot failure, insert system disk and press Enter 
8. DMA #1 error 
9. FDD controller failure 
10. Keyboard error 
11. No boot sector on fixed disk - press F1 to retry boot Timer error