unfortunatly this is not your monitor, but a problem with your video card. You most likely either A: dont have drivers installed for the network card, or B: need to reinstall the drivers for the network card.
To check this (on windows 95/98) click one time with the right mouse button on MY COMPUTER, choose properties.
Click on the device manager tab.
You will have a category DISPLAY ADAPTERS, if there is a - (minus sign) next to it, you have a problem with the video card, and need to reinstall the drivers for it. Depending on if you installed the video card yourself, or it came pre installed, you should have a cd or disk with the correct driver.
If there is a + (plus sign) next to it, click on it once, and you'll see something drop down, if it says "standard vga adapter" or something to that effect, you need to reinstall your video card drivers.