Corrupt Iso?

I'm sure Nemesis will insult me for this one, since that's all I see him do-maybe that's a cover for his lack of knowledge? Anyway, I've downloaded a couple of Iso's; Air Force Delta is one of them, and I get the .001,.002, etc. files. I use Winrar and unRar them, then I open CDRwin and try to load the cuesheet-and even though the sheet is there-it won't load. Is the game file corrupt, or am I doing something wrong? I downloaded and burned Mr.Driller, and it works fine-using the same method above. Any help?