i think you are saying the interrupt lost errors are for the seagate ?????
or better yet are you sure the interrrupt errors are for the seagate ????
you said you did a reinstall
if you installed to the seagate then the driver was working ok for the install....
and the installer's kernel was getting allong with the bios and what not.....
OK so with that said i personally from reading what you wrote think the problem is the ISA soundblester
I personally don't know how to set up a card like this unless it's working already and i can look at the windows info... especially if it's prug and pray and not pins but this might help
possibly the BIOS has a "PnP OS" or "Windows 9x support" setting that must be disabled
this might fix the usb / on board sound conflict as well. That BIOS PnP support is a total crap way windows actually needed to disable shared irq which for Linux is a disaster.
but if it's the hard drive
you could try
is this something fancy like a SATA drive ???
if your linux install is on another drive you cold
hda=none (or somehing to that effect) till you can figure this out
if you don't have more than one processor or P4 HT then make sure you didn't accidentally set the interrupt mode in the BIOS to APIC the interrupt mode should be PIC unless you are using SMP i think