Scalp sensitivity has several origins. It could be caused by an imbalance in the sebum secretion process, which leads to irritation. Pollution and stress can also irritate the scalp. In fact, pollution coats the hair in harmful elements that create a dull film over the hair and, like stress, generate free radicals.
Hard drive sizes. Hard drives come in two basic physical sizes: 2.5-inch and 3.5-inch. These sizes refer to the size of the data platters, not the size of the hard drive mechanism. Traditionally, 2.5-inch drives are used for laptops while 3.5-inch drives are used for desktop computers. Some compact desktops also use the smaller drives to enable a smaller form factor for the computer.
Here's what you need to know: The tools. The hard drive must be a 2.5-inch drive, which is the size of a normal laptop drive, have at least 160GB of space, and be no thicker than 9.5 millimeters.You will also need a USB flash drive with at least 1GB of space, a Phillips-head screwdriver, and a computer with Internet access.Sarah Tew/CNET.The process.ere's what you need to know: The tools. The hard drive must be a 2.5-inch drive, which is the size of a normal laptop drive, have at least 160GB of space, and be no thicker than 9.5 millimeters.