Adcoms and citing Extenuating Circumstances

How do adcoms view extenuating circumstances if they resulted in a few less than desired grades (C/C+) either in the beginning of your college career (freshman/soph) or later on? Do they take those into consideration before making a decision on your app? Will schools such as Harvard do this as well or will they not consider it heavily? I would truly appeciate some responses regarding this matter.

thanks for the responses LizzyM. Well the circumstances were due to severe economic circumstances due to my father getting laid off/subsequently he became terminally ill which further reduced the available finances in the household. I had to work 25 hours a week to pay for the household bills, however, even then my parents and I were evicted from our home and had to live in a shelter for sometime. All of this severely affected my mental state causing me to lose focus in school, thus underperforming for the 1.5 years. Furthermore, adjusting to college life also played a role. Additionally, my family income has been relatively low for most of my childhood, income itself was scarce. Thus, I am planning to claim the disadvantaged status. Would this help at the top schools?

Additionally, do you think this would be an acceptable answer to adcoms? Im really worried about this as I absolutely hate giving excuses for my performance....any suggestions would be greatly appreciated. Thanks again.

thanks for the response wednesdaysarmy....I guess paranoia has set in right now in concern to my grades as I will be applying in this upcoming cycle.

One last question I have is do the top level schools disregard applications that have these grades as they are trying to maintain a particular standard....or will they not weigh that part of the application heavily due to improved subsequent performance and proof of having extenuating circumstances (advisor corroborates, etc)?