First, have you tried disabling all memory caching/shadowing in the BIOS? In rare carses this can cause the dreaded 'irq no less or equal' error.
Next, you may have a damaged memory module. I recommend running MemTest to check for possible memory errors.
http://www.memtest.org/
Using the third installer, MemTest will automatically create a boot floppy for running the tests.
If an error is found, then you will need to either remove or replace the malfunctioning stick of memory, preferably with a stick of quality memory from a brand-name manufacturer like Corsair, Crucial/Micron, PNY, etc.
Good Luck,
Robert Richmond