If a fan is out, it should be replaced as soon as you can. You can get replacements at webhostsupply.com at a fair price.
We have had PCs completely destroyed due to fans on power supplies being out; we had one unit where the PS was so hot I got a 2nd degree burn on my leg when I leaned against it (that's how we knew it was out).
If a fan is out, be careful, you could lose much more than your cool :) Jale