QWhen I connect my printer through a parallel-port Iomega Zip drive, I get too many overrun messages from that HP 4.

AThe signals coursing through the parallel-port cable are bumping into each other. This can happen when driver software communicates with the printer to find out if it's out of paper or running low on ink. This works fine if you have one printer and one computer. To this scenario, our reader has added a popular peripheral -- a parallel-port Zip drive. It's typically installed between the computer and the printer, where a special chip on the Zip can act as a traffic cop, allowing printer-driver signals to bypass the drive and go to the printer. It usually works, but parallel ports really weren't designed for this much traffic.

In a perfect world, you would be able to disable the bidirectional capabilities of the printer driver using its configuration window. Another possible solution is to add a second parallel port by plugging an expansion card into your computer's innards. Make sure it is set up as ECP mode using an input/output range of 0278-027F (or 027A). Another solution, if you're running Windows 98 or a newer operating system, is to get a universal serial bus Zip drive.

I installed NetZero on my Windows 2000 machine at work without a hitch. When I tried to install it on my Windows 98 SE machine at home, I got a lot of DNS errors.

A dynamic link library (DLL) file is warring with another DLL under Windows 98 SE. The software here comes from NetZero, a California company (at http://www.netzero.comq) that provides free, ad-supported Internet access.

Windows 2000 was designed with the Internet in mind and can handle software like NetZero's easily. Older versions of Windows, including Windows 98 SE, have more problems. They use something called "sockets" -- interfaces to let programs work with the TCP/IP Internet connections provided by Windows itself. In particular, interfaces called 'winsocks' can work with one of two DLLs: winsock.dll and wsock32.dll.

It looks like these dynamic link library files are slugging it out -- one wants to handle the sockets and so does the other -- yielding domain name system (DNS) errors.

The answer is to find the older library file and get it out of the way by renaming it. On the Start menu, select the Find command and search for a file named "winsock.dll"; when it shows up in the search box, right-click on the file to rename it "winsock.d_l." Make sure you don't delete the file!

This can be a good solution to other common DLL conflict errors.

My computer freezes and I get a "Sync. out of range" message on my Dell M780 monitor.

First, pull the cable going from your monitor to the back of your computer. Make sure the pins that go into the computer's socket are pointing straight out. It is easy to bend a pin in a monitor cable, especially if you are on your knees fishing behind the CPU for the video connection. A bent pin may not allow a proper signal from the computer to the monitor.

Another culprit could be the "refresh rate" -- the number of times your computer sends a screen to your monitor in a second. This figure depends on a combination of monitor, software, and video card; for the Dell monitor named above, running at a resolution of 1024 by 768, the refresh rate should be 75 times per second, or 75 Hz for short. Believe it or not, you can damage a monitor if you set it to an incompatible refresh rate. To find your settings, go to the Start menu, choose Settings, open the Control Panel, double-click on Display and select the Adapter tab. There is normally a range of refresh rates that you can choose from there, starting at 56 Hz.

Finally, your video card could be failing, especially if the monitor's still glitchy after you set it to 75 Hz. Remember that today's video cards have lots of memory, making them more vulnerable than older cards to static electricity and power surges. Pop in a friend's card to see if the problem persists.

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 or via e-mail at jgilroy@iteminc.com.