E-stamp is one of two companies licensed by the U.S. Postal Service to distribute postage electronically. A column in yesterday's Business section incorrectly reported the company's name. (Published 01/14/2000)

Q: I saw that ad where you can print out stamps. What happens if my printer jams?

A: The U.S. Postal Service has licensed two companies to distribute postage electronically. Stamps.com credits customers with 90 percent of the value of the postage for a jammed envelope. E-stamps.com gives a full refund for any jams.

The two companies use slightly different systems. Stamps.com offers a software solution; E-stamps uses both hardware and software.

To buy postage from Stamps.com, you register online and give a credit-card number. Any time you want to print out postage, you fire up the modem. The price of the postage is then charged to your account.

E-stamps requires a $49 deposit for a device that attaches to your parallel port. You use funds transferred through a bank to set up an account (this year the company expects to make credit-card charges available.) To set up the E-stamps system, you need to have Internet Explorer on your machine. You do not need to be connected to the Internet when you print.

Both companies charge a small fee for its service, but one benefit is that it keeps you out of the post office. You never know what is going to happen in those places these days.

Q: I have a notebook computer, and I am having a hard time burning CDs with my external CD writer.

A: Here are my hardware and software guidelines for making your own CDs: Use a desktop personal computer with a SCSI (small computer system interface) and make a complete CD with one fell swoop.

Why SCSI on a desktop? SCSI is fast and has been around forever. This means the software you use to make CDs will probably have no trouble finding the drive and placing data on it.

The next best choice is to use an IDE CD writer; you will probably get similar performance. Unfortunately, our questioner was trying to use the parallel port on a notebook computer. Although this is theoretically possible, this technology is so new that sending large quantities of data through a parallel port is really asking for trouble.

For me, burning CDs is a lot like making pancakes. You pour it once and you are done pouring. Today's CD burners have a hard time precisely finding the spot on the CD to stop and then restart. Each time you attempt to start and stop, you are pushing the technology harder and harder.

Q: My computer is making a lot of unpleasant noise.

A: MP3 files usually cause raucous noise; disconnect your teenager from the computer. (I just couldn't resist including a little nerd humor; I expect a call from Comedy Central any day now.)

Every hard drive seems to have its own unique sound associated with it. You can randomly pull hard drives off the manufacturing line and one will sound slightly different from another. If that is your problem, upgrade your hard drive.

Another possibility is that the fan inside the power supply in the back of your computer is the culprit. If the noise bothers you so much, you can buy an Ultra Quiet for $65 from PC Power & Cooling Inc. (www.pcpowercooling.com).

If you invested in a very inexpensive personal computer, you may have a hard time finding a replacement power supply. This is another "gotcha" for the last decade's inexpensive machines--replacement parts are hard to find and some manufacturers are not giving support.

John Gilroy of Item Inc. is heard on WAMU-FM radio's "The Computer Guys" at 1 p.m. on the first Tuesday of the month. Send your questions to him in care of The Washington Post, 1150 15th St. NW, Washington, D.C. 20071-5302 or via e-mail at jgilroy@iteminc.com.