Although you seem to have dropped off this thread, I thought I'd provide you with what I believe to be ALL THE ANSWERS to your questions.
(1) I was correct in assuming that the three download files on the Microsoft Updates Catalog site
for hardware ID CanonS900DA58 (which is the hardware device value for your S900 printer) DO actually include the 64-bit x64 (AMD64) versions of driver-related things, and not just the 32-bit x86 (I386) versions of driver-related things.
Microsoft really has badly named the three items in the text descriptions shown on the screen
, but if you download all three you will see that they are indeed the three possible versions as named in the terrible English on the page.
But the three files are actually for (a) 32-bit Windows 7 named I386, (b) 64-bit Windows 7 named AMD64, and (c) 64-bit Windows Server 2008 R2 IA64.
(2) When you unzip these three downloaded CAB files you will see that they do provide, as I said previously, the PRNCA00r.inf driver file for the S900 (in all three flavors). Obviously you should use whichever one is relevant to your environment in which you'd like the S900 to be installed.
Note that this primary driver is actually named 4D36E979-E325-11CE-BFC1-08002BE10318.
(3) Inside the PRNCA00r.inf driver file, there is crucial information describing what is really needed to install this printer:
So in addition to this first PRNCA00r.inf and \AMD64 folder of objects, it is also required to locate the "core printer driver" named above, namely
(4) Well, just as with my story (as described on this other thread
) from two weeks ago regarding my very similar experience trying to install the x86 drivers as SECOND drivers for the Canon S800 on my existing x64 Windows 7 system that already had the S800 installed with x64 primary drivers, the location of this second driver for your S900 is NOT contained in the primary driver file PRNCA00r.inf.
Instead, it is in a separate second driver file, PRNCA001.inf. So if everything was as you-know-who intended, and if your S900 story was like my S800 story, we should find PRNCA001 on the Windows 7 installation DVD (either x86 or x64 flavors). It should also have been installed into the DriverStore\FileRepository folder (under Windows\System32) in your existing installed Windows 7 system... along with ALL driver files for ALL Windows 7-supported devices (copied from the installation DVD when your Windows 7 was installed, to be available now for exactly these kinds of situations).
However... PRNCA001 is NOT present in the DriverStore of Windows 7, and therein lies the real problem!
In the case of my S800 story, my second driver was located in PRNCA00x.inf, and that driver in turn NEEDED YET A THIRD DRIVER which was located in PRNCA00y.inf!!! And those two additional driver files ARE in the DriverStore of Windows 7. My issue was that I needed the x86 flavors, and my existing installed Windows 7 was x64. But fortunately I had access to a 32-bit Windows 7 installation DVD and through WinMount was able to extract the two additional x86 driver folders for PRNCA00x and PRNCA00y.
Now, finally, I had all three needed parts (PRNCA00t.inf, PRNCA00x.inf and PRNCA00y.inf) and navigating through the "Additional drivers' wizard finally got the x86 drivers installed for my S800.
And, in my S800 story, whereas PRNCA00t had to be retrieved from the Microsoft Update Catalog site, the other two drivers needed (PRNCA00x and PRNCA00y) were actually available on the Windows 7 installation DVDs, either x64 for 64-bit or x86 for 32-bit, inside of a compressed file named INSTALL.WIM. I had both DVDs in my possession and was able to extract from INSTALL.WIM the needed 32-bit x86 version of PRNCA00x and PRNCA00y using that program WinMount I mentioned.
(5) Unfortunately, it appears that the needed second driver file for your S900 printer, PRNCA001.inf, is NOT PRESENT ON THE Windows 7 INSTALLATION DVDs!!! My PRNCA00x and PRNCA00y folders ARE present, but your needed S900 driver folder PRNCA001 IS NOT PRESENT!
In my opinion, this is a mistake from Microsoft. Looks like it just got left off of the Windows 7 installation DVDs. There's no other explanation.
And, so, when you tried to install your S900 printer (which theoretically IS supported by Windows 7), it went to the Microsoft Updates Catalog site and found the first driver file it needed, namely PRNCA00r.inf.
But when that primary driver file needed the second "core printer driver" it was unable to locate the needed PRNCA001 folder on the Windows 7 installation DVD. Also, PRNCA001 is NOT available on the Microsoft Updates Catalog site, because it was SUPPOSED TO BE ON THE INSTALLATION DVD!!! But it's missing from the installation DVD.
Hence the inability to install the S900 "out-of-the-box" by Windows 7, either x86 or x64, despite the fact that both Canon and Microsoft claim the S900 IS supported by Windows 7.
(6) I have downloaded a version of the Vista64 installation DVD (from MSDN) and sure enough located the PRNCA001 folder, which is missing from the Windows 7 installation DVD. I could also have downloaded the Vista32 installation DVD and I'm sure it would have been there, but I am assuming you're interested in the 64-bit Windows 7 story only.
Anyway, the PRNCA001 folder IS available in the DriverStore folder of the Vista installation DVD.
So, I am guessing you can use the Vista64 DriverStore version of PRNCA001 in the Windows 7 x64 driver installation environment, just has been done many times before.
(7) Looking more completely at PRNCA00r.inf:
So these additional drivers are going to be needed... and are very likely ALL going to be found inside of PRNCA001.
(8) If you have access to a Vista64 for x64 (or Vista32 for x86 if you're talking 32-bit Windows 7) you can use it to obtain the PRNCA001 driver folder needed by PRNCA00r.
I would put the PRNCA001 folder somewhere but it's about 310MB raw or 140MB even in ZIP form. I could probably delete most of what is in there for zillions of other Canon printers, but otherwise I'd need to upload it to an FTP site for your download (I'll do that but only if you have no other alternative to offer).
If you can get your hands on a Vista64 installation DVD you can extract PRNCA001 for yourself.