You should not need a 64 bit OS to increase system page file(s) large enough to handle the data in question. You would want to add additional physical hardrives and configure as primary swap file location to Windows.
This information is something I will need to discuss with our IT dept to see if they can do soemthing like that for me.
Thanks Michael.
Note that the pagefile is unlikely to solve any problems. The memory limit is actually caused by the 32-bit OS. On a 32-bit OS, each application is limited to a total of 2GB of memory use, which can be increased to a maximum of 3GB of memory use using the 3GB or USERVA switch in your boot parameters. This is total memory usage for the application, which includes how much space it is taking up in both the pagefile and in RAM, and each application has its own 2-3GB limit. No matter how much RAM you have, and no matter how big your pagefile, a single application is still limited to 2-3GB total usage. The application can run out of memory, even if your system still has space in RAM and/or the pagefile, because it can't access any more than 2-3GB total at any one time.
The default Windows pagefile settings work fine for almost all users. You can manually set the pagefile to maximum size (4GB, on a 32-bit OS) if you wish, but this is unlikely to allow your application to use any more memory (unless the settings were already wrong, or unless your system is light on RAM to start with). It might let you have more programs open in the background without running out of memory, however, since you will also run out of memory if the total memory usage of everything running on your machine exceeds what is available in your RAM+Pagefile. All a second hard drive does is potentially speed up access to the pagefile, which may be noticeable from time to time if you are hitting the pagefile a lot. But it won't have any other effect, and will not enable you to use larger images.
Unfortunately, it gets worse... In C3D 2009 and earlier, the MAPIINSERT command will fail if you have the 3GB switch set, or if you are using a 64-bit OS. So to do this, you want to be using C3D 2010 or C3D 2011.
The only way to really have any impact on all of this is to switch to a 64-bit OS. But the new OS uses more memory as well, so in addition to something like Win 7 x64, you need a lot of RAM - preferably 8GB minimum for dual-channel systems, or 12GB minimum for tri-channel systems. C3D 2011 x64 is a memory hog, and likes you to throw as much RAM in there as possible. If you are on C3D 2010, it's still a 32-bit app, and is still limited. But on a 64-bit OS, your app can use up to 4GB of memory, instead of the 2-3GB limit you have on the 32-bit OS, so it can make quite a difference.
As another note, your app will actually run out of memory faster than that. (Remember, "memory usage" is space taken up in RAM + space taken up in the pagefile.) Internally, memory can get fragmented, much like a hard drive. So if you are on a 32-bit system, your app can ostensibly use 2GB of memory, but it will actually run out of memory when Task Manager is saying it's only used about 1.3GB of memory. If you set the 3GB switch, then your app generally runs out of memory when Task Manager says it's used about 2.1GB, and on a 64-bit OS, your app will run out of memory when Task Manager says it has used a bit under 3GB of memory. This is true of all 32-bit applications, and Civil 3D is a 32-bit application through the 2010 version. So C3D 2011 x64 is the only version that can take advantage of any more memory than that.
The upshot of all of this is that the first thing to definitely check is your image memory allocation in C3D - e.g., type MAPIOPTIONS and go to the Memory tab. Other than that, the only thing that really has any impact on a 32-bit OS is setting the 3GB switch, but that may break the MAPIINSERT command. The ideal solution is to move to a 64-bit OS with lots of RAM, which is the only thing that can really make this issue fade away. (Just remember that in order to use the MAPIINSERT command with the 3GB switch set or on a 64-bit OS, you have to be on C3D 2010 or later.)