kernel suddenly fails to boot

[Felix von Leitner <felix-linuxkernel@fefe.de>]

I'm talking about kernel 2.6.27, but I also tried 2.6.27.6.
The stunning thing is that the kernel USED to work until right about
now.  I last booted Linux on this box yesterday evening.  I have had
intermittend boot problems, but they always go away after a reset or two.
The box would freeze at boot at a message about ACPI.  Since it usually
went away after a reset, and the box is stable once it boots, I never
really cared enough to fix it.

This is a Core 2 Duo on an Abit IP35 mainboard.  The kernel is a 64-bit
kernel.

The very last line before the current freeze is:

  TIMER: vector=0x30 acpi1=0 pin1=2 apic2=-1 pin2=-1

I googled this line and found people suggesting "nolapic_timer",
"noapic" or "nolapic".  None of these work.  This is a 64-bit SMP
system.  I also tried "noacpi".  All of these get a little farther, but
still freeze the kernel before it even starts looking for SATA devices.

Windows (32-bit XP) still works on the box.

Any ideas what I could do now?

I tried updating the BIOS after this problem hit, but the BIOS update
utility said I already have the latest BIOS.

I have four gigs of RAM in the box, Windows XP only uses 3.25 of those.
Could this be a problem on the remaining RAM?

I also tried "memtest=1", which paused a little but then booted the same
kernel and also froze just the same.

Felix