Hibernating saves energy but has risks

Q What's your feeling about putting a Windows PC in hibernation?

NORM GEWIRTZ

PEMBROKE PINES, FLA.

A There's some debate about whether it's a good idea to save time and electricity by using the "hibernate mode." Let me explain.

Most Windows users are familiar with the idea of an idle computer "going to sleep." It's called "standby mode" in XP and "sleep mode" in Vista and Windows 7. When you touch the keyboard, click on the mouse or open the laptop's lid, the PC awakens. But for laptops, the standby or sleep modes are a problem, because the PC's battery continues to run down even though the computer isn't doing anything. And for Windows XP desktops, an interruption of power during standby mode causes unsaved files to be lost. (Sleep mode won't lose files this way, but it does use electricity.)

Hibernate is a deeper sleep for PCs that was designed mainly for laptops. It conserves battery power for a laptop because the PC saves your work to the hard disk and shuts off. However, when the computer awakens (by turning on the PC or lifting the laptop lid) it starts up faster than it ordinarily would, because its previous activities are retrieved from the hard disk. Whatever you were working on when the PC entered hibernate mode returns to the screen.

The main disadvantage to hibernate mode is that the PC's settings don't periodically get renewed, as they do when a PC is shut down in the traditional way. This makes it a bit more likely that your PC will have a problem and need to be rebooted, which could cause an open file to be lost. For a discussion of the pros and cons of hibernation, see tinyurl.com/yfa5brw and tinyurl.com/yepbfap. Microsoft weighs in at tinyurl.com/ybvupjg.

Not all PCs support hibernate mode. Go to Start and, in the "shutdown" menu, look to see if hibernate is among the alternatives.

Q My laptop's 140-gigabyte hard drive is filling up fast. I know there are many duplicate files on the disk, and would like to delete some of them to save disk space. Are there any programs that can identify these duplicate files and their locations so I can delete them?

BOB RICHMAN

TUCSON, ARIZ.

A At www.download.com you can find several programs, either free or for-pay, that will locate and delete duplicate files on your PC. Just search for "erase duplicate files." But be careful what you delete. Data files you've created yourself can be erased with no harm done. But with other files, beware. If you're not sure what a file is or what it does, leave it alone.

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