The unexpected appearance on your laptop screen of a solid vertical red line (or a solid line of any colour) indicates that one or more items related to the display may be failing or that environmental conditions have caused an issue. Several components must work together to produce a laptop video display, and the vertical line might be caused by one of them failing. In many cases, an improperly seated LCD data cable causes the vertical line.
Allow the laptop to acclimate to room temperature. Sometimes extremely low temperatures can cause the LCD panel components to display solid vertical lines.
Use the laptop's parallel port to connect an external monitor and switch the display to that monitor. Check the laptop user's guide on how to do this. If you don't have one, you should be able to download it from the manufacturer's website or ask a technical support representative to send it to you.
Check the external monitor display to see if the red vertical line appears. If it does not appear on the monitor, the problem is in your laptop's LCD cabling, connectors or panel. If it does appear, the problem is with either the video card or the motherboard.
Power off the laptop and disconnect the external monitor.
Discharge any static electricity in the immediate area of the laptop and wear an anti-static strap.
Follow the manufacturer's hardware installation manual to disassemble your laptop in order to gain access to the motherboard and the LCD data cable. If you don't have the manual, you should be able to download it or have it sent to you.
Confirm that the LCD data cable is properly seated and connected.
Reassemble the laptop and reboot it. If the vertical red line does not appear, your problem is solved.
Contact an authorised service centre if the red line still appears. The service centre technicians will be able to further diagnose the issue and recommend an appropriate course of action for repair.
Keep a record of the steps you take as you try to solve the problem. Should you need professional assistance, it will help you discuss your steps with the technician, saving the technician's time and your money.
Always use tools designed specifically for use with computers.