| I'm reading this thread with mounting amazement. I have never, ever,
| seen an installation of WinXP that did *not* constantly access the boot
| drive. All WinXP installations I've seen, the boot drive is constantly
| being accessed (once per second or more often). I've never seen the boot
| drive power off. When looking at the SMART data, the Start/Stop Count is
| about the same as the Power Cycle Count; the Power Off Retract Count is
| very close to 0 (if non-zero). The additional (non-boot) drives are not
| accessed, and they may power off (as per power manager settings), but
| the boot drive - never. The drive access light is, of course, always
| blinking. As far as I've been able to determine, this is because of UPnP.
|
I have UPnP disabled, as I'm not networked. I have
most services disabled. (I even disable the critical Windows
Time because I don't feel that I need atomic clock accuracy
while reporting in to Microsoft on a regular basis.

I have System File Protection killed, along with PC Health.
I have indexing disabled. System Restore disabled. Backup
nonsense disabled. Windows Update disabled. I have no
service running, that I know of, that needs to act when it's
not called upon.
I think that what you're saying makes sense. That's why
we've all been talking about excess services. But I've had
XP on other machines without constant blinking. And while
XP is a bloated hog in its default configuration, it's quite lean
and has no need to access the disk once it's been cleaned
up. (We're not talking about the disk powering down. Just
no programmatic disk access when there's no activity. My
understanding is that the disk light indicates current disk
access.)
If I don't do anything, and I shut down my firewall, I see
nohing happening in Procmon, which is as it should be. But
the disk light keeps blinking. That, and what I've found online,
make me wonder if maybe there's been a change in motherboard
designs. Maybe there's even a way to fix the problem. But
I don't know any more than that.