Hi @Tumelo Thabane.
Here’s the [https://download.lenovo.com/consumer/mobiles_pub/lenovo_g400g500g405g505g410g510_hmm.pdf|hardware maintenance manual] for your laptop model.
Go to p.74 to view the necessary pre-requisite steps and then the procedure to remove the display panel.
This will allow you to check if the video cable is securely connected to at both the motherboard end and the LCD panel end. You can also check if it has been damage where it passes through the hinge to get from the lower case to the lid.
If the cable is damaged on p.91 Item #4 you will find the FRU number (part number) for the cable. Search online using the appropriate to your model variant, part number ''only'' to find suppliers that suit you best. There are two video cables shown in the manual. The part number is sometimes on the cable itself if you wish to verify that you’re getting the correct one.