Your older versions of Avid DVD will probably work. Never used the program, but I believe its a self contained program, so the version of Avid you are running should be irrelevant. Same with most of the other software. Avid FX still came with MC7 but you have to request that license separately. Not sure if it would be considered dead… I don’t use Avid FX, and haven’t even tried to instal it on the box that i am running 8 on. There aren’t any real differences between 7 and 8 anyway, so if you need that program, stick with 7 for now.
How far can you upgrade depends on when “a few years ago” was. If your 4 years of upgrads ran out 1 year ago, than you can probably go to MC 7. You have to go to the licence page on the avid website and look around for the upgrades area. From there you can request a license upgrade. It will ask you for your original System id and serial number, and will notify you if your upgrade request is valid.
You do not have to install 5.5, then 6., then 6.5, then 7…you can jump to what ever version you want, once your upgraded license has been email to you. Every install of avid is based on uninstalling old version anyway, so there is no benefit to working your way up the ladder. My guess is, based on the timing of when that 4 years of upgrades started, you are eligible for a MC 6.5 or 7 license.
Just download 7, install it and see how far you get. Nobody is going to come crashing through your door because you aren’t eligible for a free upgrade. If you have to roll back to 6.5, then, roll back. The sequences you’ve built in the past will all open with pretty much any version. You may have some effects that have changed, but your timelines will open.
Glenn