MacBook Pro (2006 OS X 10.6.3) won't restart to finish software update (10.6.8)

Question

New hard drive, fresh install of 10.6.3
Tried to update to 10.6.8
MacBook Pro (2006) won't restart to finish the update. It only turns off.
I can turn the machine back on, but the update has not been installed.
Any help will be greatly appreciated.
Thanks.

Answer 1

There may be a redirect issue if an adware software has been
installed by accident or by intent; usually if someone goes to a
web site where questionable downloads of software are free,
there may be (included, added to) the packet you get, adware
or perhaps even malware.
So, if this is the case, the symptoms you say are part of this
experience may be related to an adware or other badware
running in the background. A 'cleanmymac' or 'mackeeper'
can also mess up a Mac computer, & they are not advised.
Several posts to the ASC discussions are about these kinds
of things and many point back to a user going to some web
site and downloading something. A click can do it.
A way to help find some evidence of certain kinds of add-ons
(outside of looking into the Browser's add-ons and see about
deleting those that relate to odd behavior, or badware) such
as adware, one could get and use this free utility & get a
report of general system info, and then post it online to see
if someone can spot some of the characteristics adware or
other malware may have included in the system.
There is another way to get a more lengthy report than etrecheck
as Linc Davis has posted, that uses more detailed effort on the
part of the user, in order to get a larger fuller report.
This is the short and easy way to look for a few clues that may
be addressed through using advice in TheSafeMac guide.
•EtreCheck: (also click on read-more)
http://www.etresoft.com/etrecheck
The report from the above may be helpful along with info in the
site below. Note there are other guides in TheSafeMac, too.
•Adware Removal Guide:
http://www.thesafemac.com/arg/
Hopefully the issue with the browser can be resolved in one
of up to three/four different ways, depending on what it is.
PS: recent updates to some OS X versions, etc do not
include update to Snow Leopard; only later systems.
{by the time I write all this, you may already have a reply}
Good luck & happy computing!