hello vimobhana, can you try launching firefox in safe mode by pressing the shift key while it is starting and see if the issue is occurring there too? maybe a theme or hardware acceleration is interfering here...

if safemode is working, you can try disabling hardware acceleration in firefox > options > advanced > general and or disable addons that might cause the problem. it also would be interesting which graphics hardware (adapter description, driver date & driver version) you are using - you can access this information in firefox > help > troubleshooting information towards the bottom of that page... thank you

Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

from another user we found out that this might be related to malware, could you see if you have the same addons installed, remove/disable them & run a in-depth scan of your system with security software - see https://support.mozilla.org/en-US/questions/940393#answer-377118