Hi,
http://support.apple.com/kb/DL1638
Download and extract the bootcamp 5.0.5033.zip
Unpack and copy the extracted file onto the windows desktop.
got to start > programs > accessories > cmd prompt (run as administrator)
....now highlight only the selection, then right or cmd + click and run as administrator (note: if you cannot right click, you can also highlight the selection and press shift+F10 to bring up the context menu).
In the cmd box navigate to the bootcamp folder on the desktop, will be something like this:
cd Desktop (press enter)
or if that doesn't work, then:
cd\
cd users
cd (your user name)
cd desktop
cd bootcamp5.0.5033 (whatever the bootcamp folder name is)
cd bootcamp
cd drivers
cd apple
you can then type:
dir
This will list the folder contents.
Once you are in the folder where you can see the bootcamp.msi file (note: you will probably only see the filename as bootcamp and 'type' as application in the windows environment) then type the following:
msiexec /i bootcamp.msi
This will launch the bootcamp application. It may look like it freezes when the nvidia drivers are installed, but be patient - it can take a few minutes until it gets through that and the progress bar did not progress on my installation.
Also, I've seen a few people offer up the 'troubleshoot mode' installation fix (you've probbly already come across this fix if you have found this post, so no point me covering that) which did not work for me. The above 'setup.exe' was not successful for me either.
A lot of posts bang on about running the 'bootcamp64.msi' file, though seeing as this version of bootcamp only runs 64 bit software, there's no reason to call it 'x64' - hence, it's only 'bootcamp'.
I ran this fine on a Mid 2008 15" MBP A1226
The only thing I need now is to see if I can fix the key mapping... is there an app like 'MagicPrefs' I can run in the windows environment that anyone can suggest? (Running a UK machine with a US keyboard - long story).