CD drive can only talk in its native lauguage

Q. We have a Gateway P120 with a 6X CD-ROM drive. Our son made a CD-ROM disc from his computer for my husband to use. When we put it in the drive, absolutely nothing happens and the system doesn't recognize there is a disc in the drive. When we put it in our new computer, a Gateway 450, it works just fine. It also works on our son's computer. What do you think could be the problem? Commercial CDs work just fine.

- Jill Eshenbaugh

jeshenba@telebyte.net

A. It may seem like CDs and CD drives are all alike but they are not. Commercial CDs have a metallic reflective layer that is placed directly against the clear base of the disc. This metallic layer has been molded with pits during manufacturing to contain the data. When the CD is played, the CD drive employs a light to "read" the pits. When the beam hits a flat area, the light is reflected directly back. When the beam hits a pit, it is diffused. The drive reads these differences in reflectivity as data. CD-R discs, on the other hand, require an extra layer of light-sensitive dye to record the data. When the disc is exposed to the recording laser beam, it changes color and reflectivity. That's why you can clearly see a darker band on CD-R discs where data has been recorded. Anyway, with CD-R discs, the light beam reflects off the changed spots in the light-sensitive dye. Rewritable discs (CD-RW) employ yet another technology for recording data involving compounds that can be "melted" by the laser beam so that they can be rerecorded with data. The long and the short of it is that some CD drives - and especially older ones - may not be good at reading CD-R or CD-RW discs while they may do a perfectly fine job of reading commercial CDs.

Q. I leave my computer on overnight. I come in the next morning and the only thing on the screen is a flashing, white cursor in the upper left corner of the screen. I do a Control-Alt-Delete and nothing happens. The only thing I can do is turn the computer off and back on again. No matter what I do, the screen stays black with the blinking cursor in the upper corner.

- Jim Horn

Redmond

A. Never happens during the day, eh? You've got some program loaded that is misbehaving. The first step in troubleshooting this kind of problem is to look for programs that might be scheduled to activate at night or after long periods of inactivity, such as screen savers or an antivirus or backup program. Disable those programs and see if that removes your problem. If it does, reactivate each program one by one until your problem returns. Then you'll know which is the culprit.

It's possible, by the way, that the program causing the problem may have been running previously without incident. It could be that you have since added a driver or DLL file that conflicts with the application.

Q. It is easy to add a printer in Windows 98 by using the Add Printer feature. But what is the "right" way to remove a printer?

- Gabriela

A. Call me lazy, but I just leave the old printer driver installed. Printer drivers are small in size and, alas, can be tricky to track down on your drive. And, as you seem to have discovered, simply deleting the printer entry in the Windows Printer folder does nothing to clean the old files off the drive. Nor does the utility for adding and removing hardware help, since it lists just about every peripheral connected to your computer except most printers.

If you really want to get rid of those drivers and you don't want to muck around searching directories and editing the Windows registry, you may want to consider investing in a third-party uninstaller, such as UnInstaller from MacAfee or Norton CleanSweep from Symantec. These programs will track where files are installed when you load a program and they make it easier to remove those files when you no longer need the application or device.

Q&A by Patrick Marshall appears Sundays in the Personal Technology section of The Seattle Times. Questions can be sent by e-mail to ptech@seatimes.com or pgmarshall@uswest.net or by postal mail at Q&A/Technology, The Seattle Times, P.O. Box 70, Seattle WA 98111.