Is a STOP 0x0000009F (DRIVER_POWER_STATE_FAILURE) BSOD a sign of hardware trouble?

I've got a Gateway P7811FX that dual-boots Win7 and Vista. It was running great for over a year until a few weeks ago when I got my first-ever BSOD. As the title says, the code was 9F, which when I Googled it seems to mostly happen when changing power states (nope) or when using a Firewire hard drive (also nope).

My first suspicion was a driver issue, Win7 still being new-ish and all, and having recently updated my video card drivers, so I booted back into Vista, which I hadn't even touched in almost a month. That ran smoothly for a day or so, but recently it also bluescreened, same STOP 9F error.

I'm starting to get worried -- it's still covered by a BB extended warranty, so if I can prove there's a hardware problem I should be able to get it fixed/replaced in short order, but nothing seems to actually cause the problem. Sometimes it runs through demanding games for hours without a hiccup, then BSOD while I have 3 tabs open in a web browser. Sometimes it bombs out when I'm not even using the computer at all -- I think once it might even have woken from having the screen off (not suspend or hibernate, though) to freeze up.

My main concern is that if I can't reproduce the problem I don't know how to prove that it happens, or determine if it's been fixed after sending it in. What should one do to troubleshoot such a problem, esp. on an integrated system like a laptop, where you can't just start swapping out components until you find the flaky one?

UPDATE: per this post I downloaded and ran BlueScreenView and a) all my BSODs have in fact been 9Fs, b) all have been caused by address "ntoskrnl.exe+71f00" (so I guess my driver theory is out?), and c) there have been 8 on Win7 alone since 11/24, though it seems like it's gotten worse in the last week. Not sure how much that helps, but there you go.

Such a problem can be explained in 2 ways: hardware or software.

However, in your particular case I understand that you never had these problems in Vista, that you didn't touch Vista since, but that the same problem is now occurring in Vista.

It is very important that there were no driver updates to Vista, but that it's now BSODing. As Vista and Win7 have the same driver base, if Windows Update was set to auto-update, then this pollutes my above logic. (please confirm that there weren't.)

For me, this is proof enough that the problem is hardware, enough to activate the warranty.

Just to make sure, you may have a look at the Event Log, run memtest86+, and install some monitoring tools:

GPU-Z will tell you the temperature of the video card
SpeedFan for the CPU
Active@ Hard Disk Monitor for the hard disk.