What is Cyclic Redundancy Check and can I still download?

How do I use this... Cyclic Redundancy Check?

• I decided to download the Sims 3 on my laptop computer, but it looks like I've hit a wall. A data error has decided to appear within a certain one of the files... and it's hindering my data progression. It says in parentheses that I should use cyclic redundancy check to scope out the error, but I have no idea how to use such a thing. I'm not that tech-smart... So please, could one of you BRIGHT minds please ENLIGHTEN me on this matter? <:'D

• Answer:

  This is basically a check for any change to a file at the byte level which is done by physically counting up the 1's and 0's. When a file has been 'damaged' from a problem copying it or been physically modified (at the programming level) the likelyhood of this value remaining the same is extremely unlikely. It is often used in security to verify that the file has not been modified in any way from its original design by hackers as even a single character change will cause the total to be different. This isn't something I would ever expect a common computer user to be asked to do since it's not just a matter of looking at the file size. I have heard of the CRC being used to check the hard drive for errors but it doesn't sound like that's what they're talking about here. My suggestion would be to locate this file on the original installation disc and overwritting your file with a fresh copy.