Pocket OPS or WIMS Portable is obsolete.  A replacement is WIMS Mobile with doForms

You can obtain Pocket OPS in one of two ways - as a self-extracting ZIP file (that has just the Pocket OPS program) or as a ISO image of a CD that contains the Pocket OPS program, full documentation, as well as all prerequisites necessary for installing & running Pocket OPS, i.e. the Microsoft .NET Framework and the Microsoft .NET Compact Framework.

You can install/upgrade using either way.

The difference is that if you choose to install via the ZIP package, you will need to download the .NET frameworks from Microsoft's website and install them.
If you already have the Microsoft .NET frameworks downloaded and installed you can download just the ZIP package, instead of the whole CD, since you're only updating the program. This should be your first choice when doing an upgrade (e.g. from version 1.6.0 to version 1.6.1)

NOTE: Upgrading from a version earlier than 1.6.0 to 1.6.0 or later is NOT supported, because starting with version 1.6.0, Pocket OPS is using the Microsoft .NET Compact Framework 2.0. You will have to download the CD-ISO setup and install the frameworks or, if downloading the ZIP package, install the frameworks manually.

1. Download the Pocket OPS ZIP file from the OPS Systems website. (You have to be registered for support)
   
   As you can see the file is much smaller than the CD image (2 MB)
   
2. Extract the ZIP to a location of your choice
   
   
   
   The ZIP contains 4 files - the release notes, a PDF with the Pocket OPS documentation and two MSI packages.
   
3. Connect your Pocket PC device to your PC using ActiveSync (detailed instructions are in the PDF manual)
   
4. Install the Microsoft .NET Framework 2.0 (if necessary) from http://www.microsoft.com/downloads/details.aspx?FamilyID=0856EACB-4362-4B0D-8EDD-AAB15C5E04F5&displaylang=en
   
5. Install the Microsoft .NET Compact Framework SP2 (if necessary) from http://www.microsoft.com/downloads/details.aspx?familyid=aea55f2f-07b5-4a8c-8a44-b4e1b196d5c0&displaylang=en
   
   NOTE: The Microsoft .NET Framework 2.0 can be installed without your device being connected to your PC. The Compact framework however requires an ActiveSync connection as it will actually install ON the device.
   
6. Run the POPS_2005_SETUP.msi file. It will install/reinstall/upgrade Pocket OPS on your device. (Detailed instructions in the PDF manual)
   
7. Run the POPS_2005_RES_SETUP.msi package. This package contains the english-language localization strings required by the Compact Framework to display built-in .NET error messages