specifics? without details, how do you expect an answer.
downloaded from steam? if so i'm sure the steam users here could guide you through it?
downloaded from torrent? if so, we can not help you on this forum.
I have no idea what "downloaded from steam" means so I`m obviously in the wrong forum. I`m not particularly knowledgeable when it comes to troubleshooting computer problems and you`ve made me feel even more inadequate. Think I`ll try and find a more friendly forum
however, if we have zero details how are we supposed to offer up a solution? we cannot magically make the problem go away. we need to know what is going on in order to offer up a solution. any forum is going to ask for the details just like i have. either that or offer up super-generic advice.
if you want generic advice without knowing any details... then.. perhaps you don't have an administrator access level account on your computer.
for starters you said you downloaded a game. this is vague. where did you get it? steam is one of the most common (legal) places to download games so this is why i mentioned it.
if you meant that you bought a game in a retail store and tried to install it then you should have mentioned this.
you aren't the only one. we ask details of everyone that posts a question. this is how those of us on the forums who answer questions can best figure out what the problem is.