hello Arpit Singhal, you have a suspicious addon present a a user.js file in your profile that might be used by adware to overwrite your preferences. please perform those steps:

1. reset firefox (this will keep your bookmarks and passwords)
2. afterwards go to the firefox menu ≡ > addons > extensions and in case there are still extensions listed there, disable them.
3. finally run a full scan of your system with different security tools like the free version of malwarebytes and adwcleaner to make sure that adware isn't present in other places of your system as well.

Troubleshoot Firefox issues caused by malware

To remove MyStartSearch virus you will need to get rid of HpUI.exe virus (Search Protect). This guide contains removal instructions explaining manual removal of HpUI.exe virus, which is a part of MyStartSearch hijacker - http://www.deletevirus.net/how-to-remove-mystartsearch-virus-for-free/ There is a video in that guide explaining removal of iStart123, which is the same thing. Don't download any program, just follow that video and you will manage to remove HpUI (Search Protect), and then MyStartSearch from your PC

every time I start Firefox I am getting this http://www.mystartsearch.com I have run your software three or four times but it still keeps on coming up.

i have done everything that was on   the board but I still having the same problem. I have the paid version of malwarebytes I have run the software three of four times without no lock. If I disable Firefox into safe mode I have no problem when I start to install the adds then it comes back on.

How do I get rid of it. I hope you can help me to so out

Hello Foxy, Have you tried to use Adwcleaner ? This (free) tool is suposed to remove mystartsearch automatically. please see this if you need a detailed guide : https://www.how-to-remove.com/mystartsearch/ Let me know if it's ok.

hi Mafre

the link you have sent me could not be found

This is somewhat embarrassing, isn’t it?

It seems we can’t find what you’re looking for. Perhaps searching, or one of the links below, can help.

Hi foxy, Sorry i mess up with the link, can you try by clicking here : https://www.how-to-remove.com/mystartsearch/ Tell me if it's ok.

hi Mafre

thank you for your help it looks like i do not have the site no longer

hello foxy ! You're welcome :)