Adobe will not activate older versions of their software.
We have a copy of CS2 that we tried to install on our new edit suite (replacing our older one). This is a second installation of the software and you're allowed 3 in total. Now I know it's old and they're up to CS4 now - but for the small amount of Photoshop work I do to prepare stills for FCP - we did not want to spend the money buying the latest version when CS2 is just fine.
To cut a long tedious story short (including 25 minutes on hold to Adobe customer service), they will not give activation codes for older versions of Creative Suite and tell you that you have to buy the latest version. If you're original installation goes awry or you get a new computer, too bad. They force you to buy it again.
I do not want to get banned from the forum so will refrain from saying what I think of Adobe's policy here ... but you can imagine I'm sure.
Yes .. I found that out (about the two activations), but the old machine, and it's CS2 installation was no more. And this would have been only my second activation - but they still told me it was too old to use.
HOWEVER ... a very helpful chap from Adobe saw my posting and phoned me and said that customer services were absolutely wrong about this. He was very annoyed about what I had been told and fixed the problem. So my opinion about Adobe has shifted somewhat ... now if only Apple was as helpful!