How do I unrar a file?

Why does it say CRC Failed? when i try to UnRAR a file i downloaded?? 10 POINTS!!?

• i tried reinstalling winrar with several diferent ones... i even tried diferent programs.. and every file i download in rar file says crc failed.. i know its not the file or the program.. because how could all files be corrupted?? i have tried many files from diferent sites and when i try to unrar the same problem... CRC failed..what settings should i change or what can i do?? remeber i have tried everything from changing programs..to different files.. so i dont believe its the files or programs... any help??

• Answer:

  CRC means (Cyclic Redundancy Check). It is an error detection mechanism used to indicate the file's integrity. CRC failure means that the file is corrupted (this is the only purpose of CRC, file error checking). You can try this: Select several files and generate a RAR file (file compression). Now, UnRAR the same file (file extraction). See if you get CRC Failed. One reason that you may get a lot of CRC Failed is when your hard drive has a lot of bad-sectors. Try to save the RAR file on another hard drive, then UnRAR it. To check if your hard drive has bad-sectors, run Chkdsk. Start --> Run... Type 'cmd' (without the quotes), then click the 'OK' button. This opens the DOS command-line window. On the DOS command-line window, type 'chkdsk C:' (without the quotes), then the 'Enter' key. Disk checking will start. Wait for disk checking to finish. There shouldn't be any error reported.