Firefox 21 is really slow on startup, I have disabled all addons, checked memory, optimized win 7, ran system mechanic but it is still slow, changed home page . IE 8.9.10 is lightning fast on startup.
Please update to Firefox 25, 21 is old and out of date. Update Firefox to the latest version
A tad faster but still slow compared to IE 8,9,10 where it starts instantly.
Note that your System Details List is showing a very old Flash 9.0 r45 version.
You should see the path of this plugin on the about:plugins page (open via the location bar) and delete this file.
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).
It is also possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.
Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.
Also, please note that IE will almost always feel like it starts up faster than Firefox, because there are portions of IE that are bundled into the rest of Windows, and start when the computer starts,so it has less work to do when it actually is opened. Firefox can't do that, meaning it might feel somewhat slower.
Is this path and file that I should delete manually?
File: NPSWF32.dll Path: C:\Windows\SysWOW64\NPSWF32.dll Version: 188.8.131.52 State: Enabled (STATE_VULNERABLE_UPDATE_AVAILABLE) Shockwave Flash 9.0 r45
Yes, that looks like the correct file.
The current releases have the version number in the name of the NPSWF32_11_X_XXX_XXX.dll file.
I deleted this file, but startup is still slow at 10 seconds compared to IE9 which is like lightning
The first start can take longer because the files aren't in the Windows disk cache, but subsequent starts should be a lot faster.
Note that it is also possible that security (anti-virus) software is causing issues by checking/monitoring read and write file actions.
Each and every fresh start is the same it takes 10 seconds for Firefox to start up even with the anti-virus disabled.