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.
Disk Wipe is a free utility for wiping data from a hard disk in a secure manner. Like Eraser, Disk Wipe includes a number of different algorithms, including DoD 5220-22.M, and Peter Guttman. The really nice thing about this utility is that it is portable, so you don't have to install it to be able to use it.