ACPI error at startup

MacBook Air, Late 2008, 128 Gig SSD HD

I've used windows 7 on my Air using Bootcamp for about 6 months. Worked perfectly at first but recently started to act up:

Sometimes works fine.
Sometimes really slow startup, stuck at windows splash screen for > 4 min. Sometimes really slow shutdown. Occasionally at slow shutdown BSOD saying DRIVER_POWER_STATE_FAILURE flashes by before system turns off.
Also sometimes slow recovery from hibernation and standby.
Above problems seem to appear randomly.

When checking the event viewer after a slow startup I get 15-20 ACPI errors (EventID 13) in a row, wasting 3+ minutes alltogether.
Recovering from sleep and hibernation i sometimes generates HAL error (EventID 12) or Disk error (EventID 11).

Had Apple service look at it and they claim nothing is wrong with the hardware, also using the computer in OSX 10.6 seems to work just fine. However it kind of looks hardware related to me since Windows worked fine for a long time at first. Tried multiple re-installs, different (legit) copys of Windows.

Is this a known type of error with Mac + Windows? I'm unsure how to proceed so I'm throwing this out there to get some clues. Grateful for any suggestions.

Heres the full bluescreen info:
Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1053

Additional information about the problem:
BCCode: 9f
BCP1: 00000003
BCP2: 85548B58
BCP3: 82D71AE0
BCP4: 865DD400
OS Version: 6_1_7601
Service Pack: 1_0
Product: 256_1