How to play really old projects?

I have some old projects that I was creating using Cubase VST 3.5 in the last 90’s. I have not been composing since, so I am not into computer music software anymore. Now (almost twenty year later) I can not find my old install CD and hardware dongle, so I wonder; Is there a way for me to play my old projects again?
Is the old Cubase versions available for download at Steinberg?

The answer is “it depends”, unfortunately. There is a way, but it depends on whether you currently have a license and in Steinberg terms, the license is contained in the physical dongle (now called USB eLicenser). Your may also have had the older parallel port type, and modern computers don’t have parallel ports any more. The point is academic if you’ve lost the dongle though – I think your only chance is to try to find any proof of purchase and then contact Steinberg support.

Then there’s the files. Depending on what system you ran Cubase VST 3.5 on, you’ll have to be able to transfer them physically so they can be accessed by a modern system – for example, there are no floppy drives anymore. If you have the files e.g. on a hard disk, then there’s the question of the format; these are probably in “.all” format, so you’d need access to a version of Cubase that can read that old format, and save in the newer “.cpr” format. The last version that could do that was Cubase 4, but Steinberg do provide a version of Cubase SX3 for download for this very purpose. The problem is, you’d need at least a Cubase SX3 license on a USB eLicenser in order to be able to run it. So, a Kafkaesque situation if ever there was one – they don’t make it easy.