In case you need it...
You can indeed try to repair the installation with the installation media. I would try with the DVD.
However, openSUSE 10.3 is getting old, and you might take the opportunity to install 11.0 or 11.1 in its place.
You might open a terminal and use the command "dmesg" and perhaps "lsmod" to see what 10.3 is doing as it boots. See also "man dmesg" and "man lsmod" for an explanation.
Was there any change in the system just before these booting deficiencies occurred?
Did you, by the way, open the BIOS Setup and look?
However, if the system boots without a problem, there should be nothing wrong with the BIOS and the POST process.