Updating Camera Raw won't eliminate DNG profiles...only an un-install would. If you download the free DNG Converter 6.4 part of the install will install all Adobe provided DNG profiles. BTW, what camera are you using where you only see the matrix profiles and are you sure you are looking at a raw file not a JPEG or TIFF?
I am not using DNG, but only the original CS2 raw files from my 5D2 and 7d. Using CS5 of course and had no problems with 6.4. The Matrix profile is shwn after clicking the Camera Calibration button in Camera Raw, and it shows as the only choice for Camera Profile Name. I normally download any updates to a flash drive so I can apply them to both computers, but this time I used the Help/Updates link in Photoshop.
My laptop, also running CS5, win-7, 64bit, and ACR 6.4.0 has no problems.
I suspect that while I was doing the Camera Raw update, Windows kicked in with some updates of it's own. Anyway, a re-install of CS5 and then updating it after checking for any Windows updates, and all is working well. Suspect that just one file got corrupted, and it would have been easier to replace that one file from my laptop, but the brute force approace worked.
What files with extension .dcp do you have in/below these folders?
Edit: Oops, took to long to respond, I see.
Couldn't open this prior to the re-install, probably corrupted, but now
293 cameras in the Adobe Standard folder, and appear to be 5 for each
camera under the specific Camera folders. All of my cameras that shoot
Raw or have ever had that shot Raw are now listed. And Camera Raw now
working again as it should.
Under the %UserProfile%..... There is only one file: Index.dat
If you're ever unsure about whether you've seen disk corruption, it's a VERY good idea to do the following:
1. Check the Windows event logs to see if any disk problems are being logged.
2. Consider (if there's no hardware fault) running CHKDSK on the volume.
3. Set up a backup process if you haven't got one already.