When you send a job to your printer, you expect to see the exact text you have on the screen reproduced on the printed page. Sometimes, however, you may see not your expected output but page after page of strange characters. These strange characters often manifest themselves in lines of asterisks, pound signs, stars and smiley faces, all lined up on the first few inches of the printed page.
Power Cycle the Printer
When you see these strange characters, power cycle the printer and clear its memory. Start by physically pulling the power cord, then remove all the paper from the tray. Leave the printer off for about 10 to 15 minutes, then plug it back in and fill the printer tray. This should clear the printer's memory and allow normal operations to improve. You need to go on to further troubleshooting only if the problem persists after the power cycle is complete.
Manufacturers may be aware of issues with a particular printer and have developed a solution. The best way to find out about any strange character issues with your printer is to visit the support section of the manufacturer's website. Look up the FAQ for your model, and do a search for "strange characters" or "garbage characters" and see what results you get. In many cases you can find a fix for the problem right there, often a new driver you can download and install.
Uninstall the Printer
A corrupt driver can cause issues that result in strange characters and garbage output. If you have a printer experiencing this problem, you should immediately uninstall the printer, then reinstall it using the most recent driver from the manufacturer's website. Just log on to the website and look for the support or drivers section. Download the appropriate driver for your operating system, and install it according to the instructions listed on the site. Uninstalling the printer and reinstalling it with the updated driver is the best way to rule out a corrupt driver as the source of the problem.
In some cases a loose or defective printer cable can cause problems with strange characters. When the cable is loose, communication with the printer may be interrupted, causing the unit to misinterpret the information it is receiving. The same thing can happen if the cable is defective. Start by checking the tightness of the cable, both at the printer end and at the computer end. Verify that the cable is tight, then replace it with a new cable if the problem persists.