YES, do let it install !
ACPI stands for Advanced Configuration and Power Interface
This is a firmware interface in BIOS, that allows operating systems to call BIOS routines for managing power related
system hardware parameters:
1) CPU mode (Sn states): Run, Suspend, Sleep, hibernate ...
2) CPU Voltage and frequency
3) Fan speed... etc....
Multi-processor PC, means that the firmware has detected a
multi processor system or is confused by the hardware. There
are several conditions that cause this interpretation:
a) A genuine multi-CPU Board with 2 or 4 CPU sockets.
b) A multi-core, single CPU, such as the new Intel
CORE-2 DUO series...
c) Interleaved RAM on a single CPU, with dual buses.
This is OK, and nothing to worry about.
The ACPI interface is very advanced and complex, about 3500
pages of engineering specifications, and most P'sC only use
a very tiny sub-set of its capability.
The ground level ACPI settings and options are contained within
the system BIOS. The best solution is to set them to their
default settings, unless you know what all the settings mean.
To access the BIOS settings, on most PC's:
Press DEL or F1 right after the POST/memory test.
Depending on the BIOS settings, the operating system's HAL
(Hardware Abstraction Layer) may need to install additional
interface and control drivers.
On a desktop, these so called "GREEN" power saving features
are a horrible pain in the neck. and I would disable them all
together, unless you pay $20,000 per months for your
On a laptop, however, these drivers are fairly important to
significantly extend your battery life, so you should enable
If the computer was restored to factory condition, by pressing
a magic "blue" button, these drivers are part of the original factory installation and should be installed, just let the PC recursively do its thing, until it calms down.
Most name brand manufactures provide a hidden partition on
the hard driver, typically a FAT-32, which contains a complete
set of recovery files, unique to the PC model and all the features
This restore partition is most often formatted as FAT-32,
because FAT can be accessed using primitive BIOS calls
while NTFS cannot:
1) FAT16 = Original DOS, support drives < 2GB only.
2) FAT32 = Extended FAT-16, for larger drives.
3) NTFS = Windows NT, 2000, XP, and Vista only.
Cannot be accessed before Windows is running.
The manufacturer then provides a boot/ BIOS hook,
activated by their MAGIC or BLUE button, which in turn
un-hides this restore partition, loads Windows PE
(a special pre-install/ repair version of windows),
and then loads the recovery program.
In any event, you need to let the installation/ restore process
finish, including the ACPI install.
After several annoying re-boot cycles, this process will (should)
restore the PC to original factory conditions.
Factory restoration is, however, a very drastic and destructive process. All your settings are lost and (depending on the particular system) sometimes your data as well. I should
be avoided like a biker on a bad day.
It is a good idea to back-up everything possible, before taking such a drastic step, and I prefer to use an external USB drive for doing this. Also this step should only be used as a last resort.
However, in your case, all the DRASTIC and LOSSY part has
happened already, so you have no choice but to proceed and
let it finish. Once the restoration is complete, the FAT-32
partition should disappear, that is it will be hidden again.
Do not damage this partitions, unless you own a set of factory
repair CD's !!!
It is also a good idea to request the FACTORY repair CD's for
your machine from the manufacturer and keep them in a safe
Once you have the recovery CD's, you can delete the hidden
recovery partition, and use the recovered space for more
useful things, such as data or applications.
To do this, you need a partition manager tool, such a Norton's
Partition Magic or Acronis tools. Norton's bought the original
tool from Power Quest, and royally phluquified it, so I much
prefer Acronis these days.
Also after you PC is fully restored, go into the power settings
in the control panel (or via the screen saver settings) and
configure the ACPI as you wish. But you must install it first.
Hope this answers all your questions,
please rate my answers.