Lightroom 3 crashes on import every time

Question

Hi.
I have just installed the demo version of Lightroom 3 on my Windows XP (3GB RAM). It installed and opened fine, but when I click on the "import" button, it crashes every single time. I have not been able to import anything at all. I have tried folders and just one single image (I tried drag-n-dropping it too)
I have re-installed the program once to no avail. I have deleted the prefs (or so I think) and tried numerous other things.
Very thankful for any help!
Regards
Sebastian

Answer 1

32-bit operating systems are limited to 32 bits of address space.  This is 4GB.
Windows places some additional restrictions on this by reserving 2GB of total physical RAM for the system, leaving 2GB for user processes. Because each process needs space for various libraries and stacks and other private stuff, the theoretical 2GB is actually somewhat less, but it depends on the application the exact value.
The /3G switch is a way to take part of the system memory away and give it to user processes, but not all applications and environments can operate in such an environment. It is only recommended (barely) for Windows servers where you need to make sure some small set of services have the largest user space.
Lr is not "restricted" to 1Gb. As a 32-bit or 64-bit application it will ask for whatever resources it needs to the maximum addressable space and will use that or make do and recover (in most case) if the resources are unavailable.  If this means Lr starts swapping to virtual disk, so be it. Since Lr has to share that physical RAM with other processes on the machine, it is up to the OS to balance what it can give out.  It will usually give foreground user apps as much as it can, but memory is a precious resource, and every process can ask for it at any time.
64-bit version of the Windows OS and 64-bit applications can theoretically see a 64-bit address space, but Windows (and, actually, most other operating systems) restricts the user space to some much reasonable smaller number that depends on the flavour of Windows (there are something like 7 kinds of Windows 7.) In the "premium" flavours it is something like 16Gb, with 15Gb being the reasonable maximum because of libraries, stacks &etc.  This is a little different because 64-bit pointers and stacks are twice the width of their 32-bit counter-parts.
(This is all from memory, BTW, and Windows memory management is a twisty maze of passages, all different.  See here: http://msdn.microsoft.com/en-us/library/aa384271(VS.85).aspx)