W500 hangs at Classpnp.sys with fresh install of Win7

[Zak]

I can install Windows 7 on my W500 without a problem. I've reinstalled several times, both with and without reformatting. I previously had a working install, but it started hanging during boot for unknown reasons; booting in safe mode revealed that it hangs at Classpnp.sys. I've tried setting the SATA controller to compatibility mode, then reformatting and reinstalling. I get the same result. I've tried both 32-bit and 64-bit.

I normally run Linux and have a working Linux install on the same hard drive. I've had no issues in the 2-3 weeks since Windows first failed to boot. Windows has not booted except from the install CD since. I can read and write to the Windows partition normally. I used the same Win7 CD to install to a Virtualbox VM, and the Classpnp.sys file from that VM has the same MD5 checksum as the one on the Windows install (32-bit checked).

I think a BIOS setting may be to blame. I did make some changes before this problem started, but I'm not sure if I booted Windows successfully afterward; I don't use it every day. I'm looking for a list of BIOS settings that are known to cause issues with Windows 7, or anything else that might cause this issue that I haven't yet ruled out.

[Zak]

I updated my BIOS to 3.12, as the changelogs suggested 2.x might not be compatible with Windows 7. It still doesn't boot, even after another clean install.

[Zak]

After further research and experimentation, I've discovered that it doesn't actually fail to boot. It just takes over 5 minutes.