Michelle, it really isn't legal.
I think it is legal, you download it for free right at the adobe website, you just need to have an account.
here is the link from one of the sources with references to ADOBE resources. and there r more. sorry guys
with all the research myself and someone else did a couple days ago about this it appeared to be free in the beginning. yes there is a link and u can download it. it is one of 2 things to the best of my understanding...a free trial version that they gave a serial number to those who already owned it...or its a link that was shared that shouldn't be and it definitely illegal according to ADOBE. Adobe has stated emphatically that they do not now or will they ever give away free software to the general public.
UPDATE: no it still isn't legally free. but it is free with a license as long as the page is there. please read some of the info out there like the forum discussion linked on the page i first gave u. it was meant for people who already had the software legally. at this time u need an adobe ID and the serial number is still available and no activation is required (that was the cause of this whole mess due to its age) Adobe still stands by it isn't free but a fix.
the discussions are actually quite interesting using (Adobe's Forum) this is from a USER not adobe (and many others have said the same thing) The EULA is the only contract necessary to adhere to, and the end user here, having gotten the software from adobe is in the clear (because EULA never says it must be purchased) Adobe has known this link was available to all and not fixed it.
please do your research and decide how u want to proceed. until Adobe says differently it is an illegal copy to own if u did not own it already. not sure if Adobe is going to do anything about it. Maybe after all the internet buzz they r just acting like nothings changed but not going to stop anyone. i do NOT know so do your own research.
while i have CS5 i also have CS2 and it works fine on windows 7 just obviously doesn't have the newer functions.
hope that helps