Yasu plntzas,

Since you have a MKIII, the last operating system version that was developed for your system is 3-1/63.

This OS version can be found in V22 of the upgrade disks. So there's no point in getting V28, as all the versions after V22 contain enhancements for MKIV systems only.

You can get a copy of the V22 software from http://www.e38.org/nav/

If you have OS version 3-1/31 your upgrade path is a 2 step process.

First of all you'll need to download V18-KEY.ZIP and upgrade your system using the OS and CD-KEY provided in that file.

Then you can download V22_1_CLONECD.RAR and use an application like WINRAR to extract the CCD file which you'll need to create to upgrade to V22 (OS 3-1/63)

Hope this information helps.