I installed the upgrade version of Lightroom 5 (running 3.6) on a Dell laptop with 4GB RAM and Windows 7 Ultimate. The install never asked for the serial number. When I try to start it I get the folowing message: "The application was unable to start correctly (0xc000007b). Click OK to close the application."
You are not the first one to report this, happens in several versions of LR .
It's nothing to do with the build. Something else on your system, unrelated to Lightroom, has broken/removed those Microsoft DLLs in the default Windows libraries (often something called iLivid was the culprit). The "fix" is simply putting clean versions of the DLLs into an Adobe library so that Lightroom stops trying to use the broken/deleted ones.
That danged thing again. It loads like a virus and is the gift that keeps on "F'ing" me. Nice to know. Sadly there is no true way to repair the damage that thing does to a system from what I can tell.
Wouldn't a repair re-install of Windows clean things up? Although I vaguely recall from the time that this problem started happening that it was one of the users on the forum who first identified the cause (i.e iLivid), and fixed it by sourcing other versions of the two DLLs and restoring them to the default location. Might be worth doing a search on the forum to dig out that old thread, there may be some useful tips in it.
I am not a expert on this, but the Adobe LR installer could place the correct versions of the DLLs in the LR 'Program Files' or 'Program Files (x86)' folder.
For example the msvcr100.dll is found in the 'Program files' folder of ImageMagick, RawDigger, Capture One 7, Google Earth, Java, Firefox and of course in the Windows System32 and SysWoW64 folder.
I'm no expert either, but I'd think Adobe might feel uncomfortable messing with the Windows Program Files.....if they'd even be allowed to. But yes, given what's happened I would have thought they might have considered including them in their future builds. Maybe they will.....