is this a legal game download(advice please)

i bought a copy of doom 3 (im a bit late i know) it cost £10.00, when i got home i realized it was mac copy and ive got a pc. so i dloaded a pc copy and installed it and used the key that was on the doom (mac) box and it worked.... is this legal???,,, as i bought a legitimate copy

 

Maybe the best way to find out is to have a look at the wording of the end user licence agreement. If from reading this, it appears the licence allows you to install and use the software, I'd say you're probably alright. I know those EULAs are usually quite a boring read, but somewhere in there it will probably tell you what's what.

Or if it's possible, quote some of the text on here, or maybe there's a link to it so someone can have a look and see what it says.

Morally, I wouldn't say you've done anything wrong, as you've actually paid for your use of the software. The only grey area is the fact that you physically bought the Mac version. If it was me, I'd still sleep at night with a clear conscience, but it's a matter of what seems right to you.