Black Candles are bearish lines in candlestick and candlevolume charts. They signify that the closing is lower than opening for that time period.
CHKDSK, short for Check Disk, is a utility that checks the integrity of the files and file structure of your hard disk. I'll walk you through it. I have disk problems and you said I should run CHKDSK. Great.
It is similar to the fsck command in Unix. On Windows NT operating systems, CHKDSK can also check the disk surface for bad sectors and mark them (in MS-DOS 6.x and Windows 9x, this is a task done by Microsoft ScanDisk).