The said:
I've been given a desktop machine with W7 on it,
but with a single-core CPU in it now.
There is also a dual-core CPU that was never installed.
Can W7 see and use the dual-core without a reinstall,
OR, like older versions of Windows, do I need to reinstall
W7 after installing the newer CPU??
On the older OSes (Win2K forward), some HALs were
easier to transition from than others.
Yours should be the easy case - a move from a single
core ACPI HAL to a multicore ACPI HAL. It should be
possible to do that with the equivalent of a
"driver update". It should not require a re-installation,
unless the original install was horribly botched. I don't
even know if the modern Windows support non-ACPI installations.
The reason this should be relatively easy, is the registry
entries for ACPI, power scheme and the like, were put there
during installation. Only a few DLLs or kernel runtime file
need to change.
You go to Device Manager, look for the Computer entry, and
do properties on it. That's where the HAL driver details
are located. The OS (kernel) consists of several files that
characterize the hardware abstraction layer. A driver change,
is what changes those files.
If a non-ACPI HAL is in place, there are something like
a couple hundred registry entries, that would be different
or non-existent. And then, the update from non-ACPI to
some flavor of ACPI, takes more repair work. It's theoretically
possible to fix something like that, but I haven't heard
of a recipe.
I Googled on "HAL change", and found this reference. It
suggests a few different Windows OSes, use the driver method.
http://kb.vmware.com/selfservice/mi...nguage=en_US&cmd=displayKC&externalId=1003978
I think I've done "ACPI Uniprocessor PC" to "ACPI Multiprocessor PC".
http://support.microsoft.com/kb/309283
Don't forget to back up your OS and SYSTEM RESERVED partitions,
before "doing surgery". With any procedure, there are risks.
Windows 7 doesn't make doing a Repair Install particularly easy,
but a Repair Install would likely be enough to fix any tough
cases (such as an original non-ACPI install). See the
309283 KB article, for the names of the various HALs that
are possible.
Paul