Admin site and main site running very slow

You’ve got a number of high resolution images loading on your home page for the slider which is one of the reasons it is slowing down. With sliders they load ALL of the images at once even though you may not see them instantly. I would look at optimising your images.

https://tinypng.com/

Is a great tool and they also have a WordPress plugin you can use to optimise images as you upload them.

Thanks a lot for your prompt response but how come my admin page is not responding.The slider was there earlier as well but even I am not able to navigate to pages and settings in admin.

The login page loads fine. If the admin area once logged in is slow I would suggest disabling all plugins and checking the performance and then re-enable each plugin one at a time to see which one is slowing down your site.

Right, but its taking ages to disable the plugins as plugin page is not being displayed properly. I have tried restoring files 3 days back but still its dead. I am not able to relate the issue.Why does the admin is not responding at all ??

Another point I would like to add, do I need to delete the plugins or just deactivating will do.

You can disable plugins by FTP. Simply login to your FTP server and goto wp-content/plugins change the name of the plugin folders to include an extra character so for example jetpack change to jetpack_. WordPress will then disable the plugin.

You don’t need to delete anything just yet, start with disabling.