This is mostly for me, to track my progress dealing with this problem, and for others to find, if they have the same problem. (Progress in trying to fix my recent BSOD problem with my Dell 8600).

Dell Support Community Post:

Hey, guys. I've been loving my Inspiron 8600, which is a 1.6 Ghz Pentium M w/1GB RAM, Dell TrueMobile 802.11 b/g, 2x DVD+RW internal drive, and Bluetooth, running Windows XP with all recent updates from Microsoft.

However, a couple of weeks ago, my machine started blue screening every few hours, just randomly -- whether I was active on the machine or not. Microsoft's "Serious Error" tracking shows it as a device driver problem, but they don't have any specifics on the problem. The message I'm getting upon crash is "IRQ_NOT_LESS_THAN_EQUAL".

Has anyone else been having this problem? I don't have a lot of fancy peripherals attached to my computer. Besides what is in the machine itself, I use a Logitech USB mouse, and external firewire hard disk, and occasionally a various digicam media readers. But even when all is unplugged from the system, it will still crash.

Today, I went through all the Dell drivers for my machine and made sure everything, including machine BIOS and DVD+RW drive firmware, were current. I hope it solves the problem. But I wanted to get a note out to solicit any similar stories there might be out there, if they exist.

The other thing I should say is that sometimes when I shut the machine down, I'll see a 1-pixel gray line run across the XP shut-down screen, right before it shuts down.

I also had the screen turn into a medly of colored blocks once -- almost like old-school ANSI art -- when closed my notebook and came back to it later. The screen stayed on, and the computer became very hot (while closed, with the screen on). It refused to respond to CONTROL-ALT-DELETE, and I had to turn it off by holding down the power button for 5 seconds.

Eric Cheng

Links I've found with info about IRQ_NOT_LESS_THAN_EQUAL:;f=24;t=000489

Things to try (from forums):

Try: Update Windows XP -- all drivers and BIOS from Windows Update and from Dell Support.
Result: No dice.

Try: Disable useless things that use IRQs
Result: Disabled serial port, parallel port, and modem. Still bluescreens.

Try: Remove hardware of some of the devices sharing an IRQ (I have eight different devices on IRQ 11, for some reason), and see if Windows assigns a different IRQ upon reinstall.
Result: Can't really do this with a notebook. :(

Try: Advanced > Chip Configuration
- SDRAM Configuration > from By SPD to User Define
- SET SDRAM CAS Latency > from 2.5T to 2T. (apparently 2.5T is quite unstable...?)
Result: No option in Dell notebook BIOS

Try: Set RAM speed manually in BIOS, instead of using Auto
Result: No option in Dell notebook BIOS

Try: Disable ACPI (not sure if I can do this safely without a complete reinstall)
Result: Not really a good option with a notebook, since power management goes out the door.

Try: Yank one of my 512 MB sticks out, and test. Yank the other, and test.

Try: Throw computer out of 14th story apartment, and see if it works better.

I hate computers.