OK, as promised, here are the results of booting with the nVidia card and using the option "knoppix xmodule=nv" from the F2 screen.

Sadly it doesn't help , and the symptoms are as far as I can see exactly the same as before. The Startup sound is chopped up in the same way (and BTW the shutdown sound is similarly mangled), and the mouse is frozen.

Once again, putting my old video card back makes everything work again.

Anyway, back to the broken case. I used Ctrl_Alt_F1 to get back to the console, and started some analysis, saving the following files, whose names ought to be self-explanitory:

Code:
lspci.txt
lsmod.txt
dmesg.txt
fstab
modules.conf
XF86Config*
These files can be found in full here: http://www.netg.se/~hugge/archives/k...ia_problem.bz2 in case anyone is interested in helping to track this one down.

The relevant lines from lspci are here:

Code:
00:01.0 PCI bridge: Intel Corp. 440LX/EX - 82443LX/EX AGP bridge (rev 03) (prog-if 00 [Normal decode])
	Flags: bus master, 66Mhz, medium devsel, latency 64
	Bus: primary=00, secondary=01, subordinate=01, sec-latency=64
	Memory behind bridge: fd000000-fdffffff
	Prefetchable memory behind bridge: d0000000-d7ffffff


01:00.0 VGA compatible controller: nVidia Corporation NV11 [GeForce2 MX DDR] (rev b2) (prog-if 00 [VGA])
	Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 11
	Memory at fd000000 (32-bit, non-prefetchable) [size=16M]
	Memory at d0000000 (32-bit, prefetchable) [size=128M]
	Expansion ROM at <unassigned> [disabled] [size=64K]
	Capabilities: [60] Power Management version 2
	Capabilities: [44] AGP version 2.0
I still reckon it's more likely to be an interrupt-related problem, as the vesa driver that knoppix selects exhibits the same symptoms as the nv driver that I selected. Of course I am not 100% sure that I used the right option, so could anyone please confirm that this
Code:
knoppix xmodule=nv
is the right thing to type at the F2 screen?

Any other ideas, anyone? Maybe the card is simply broken in a really strange way that only affects the mouse and soundcard, but I must admit it seems unlikely .