Played through a bit and everything seems fine! Here's how I fixed it:
1) find your ME3 installation directory; this will be wherever Origin decided to put it unless you changed that before starting; you can check by looking at the 1st tab in the origin/application settings menu (from within origin). Navigate to ...\mass effect 3 \ _installation \ VC \ vc2005sp1 (spaces added for clarity)
2) from there try running vcredist_x86.exe. If you have the same error as me, they will fail with an error similar to this:
"Error creating process <c:\users\appdata\local\temp\ixp000.tmp\vcredi~1.exe>. Reason: The system cannot find the file specified."
The file path between the < and > may be different, but stop here and make a note of it.
3) install winRAR if you don't already have it; it's an archive tool thar reads .rar and .zip files, and the free trial version will be enough for this fix.
4) Back in your vc2005sp1 folder, right click on the first installer, and select extract here. This should unpack the contents of the .exe file into the same folder. This should consist of the file mentioned in the error message above; in the case of this example, "vcredi~1.exe". Keep this window open for later.
5) Next, using the path from the error message above, open a new window and create the folders that are noted within <>'s. So for instance, for the example above I would go to "c:\users", then either create a folder called "appdata" or open it if one already exists; then I would do the same for "local" (create or open), then "temp", then "ixp000.tmp".
6) once you have created & opened the final folder, move the extracted files from step 4 into it (by either copy & pasting or dragging).
7) run vcredist_x86.exe again; this time it should work properly, as we have moved the file the error requested into the folder it was looking in. If you get a similar message again however, note the path again, create it and copy the files there as you did in steps 2, 5 & 6 above, then repeat step 7.
8) if you are running a 64-bit OS, then you may need to repeat steps 2-7 for vcredist_x64.exe.
9) Run installer from origin again; this time it should install VC++ successfully.
Good luck!
