In the end you might find yourself unable to solve your problems and need help from someone else. The most efficient way is either to ask someone local or in your nearest Linux user group, search the web for the nearest one.
Another possibility is to ask on Usenet News in one of the many, many newsgroups available. The problem is that these have such a high volume and noise (called low signal-to-noise ratio) that your question can easily fall through unanswered.
No matter where you ask it is important to ask well or you will not be taken seriously. Saying just my disk does not work is not going to help you and instead the noise level is increased even further and if you are lucky someone will ask you to clarify.
Instead describe your problems in some detail that will enable people to help you. The problem could lie somewhere you did not expect. Therefore you are advised to list the following information about your system:
Chip set (LX, BX etc)
Bus (ISA, VESA, PCI etc)
Expansion cards used (Disk controllers, video, IO etc.)
BIOS (On motherboard and possibly SCSI host adapters)
LILO, if used
Linux kernel version as well as possible modifications and patches
Kernel parameters, if any
Software that shows the error (with version number or date)
Type of disk drives with manufacturer name, version and type
Other relevant peripherals
Remember that booting text is logged to /var/log/messages which can answer most of the questions above. Obviously if the drives fail you might not be able to get the log saved to disk but you can at least scroll back up the screen using the SHIFT and PAGE UP keys. It may also be useful to include part of this in your request for help but do not go overboard, keep it brief as a complete log file dumped to Usenet News is more than a little annoying.