Since you deleted your profile, you might not have any accumulated crash data, but if you have created a new one, you might be able to extract some now. Please check the support article "Firefox Crashes" (especially the last section) for steps to get those crash IDs, and then post some of the recent ones here.

If that's not possible, have you tried Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can start Firefox in Safe Mode by holding down the Shift key when clicking or double-clicking the Firefox icon.

In the small dialog that appears, click "Start in Safe Mode" (not Reset)

Any difference?

I've tried safe mode (both command line and shift) but ff crashes immediately with the "Mozilla Crash Reporter"

Crash ID: bp-514360f3-ebd7-4e47-99dd-d73d22140729

AvailablePageFile: 33966383104 AvailablePhysicalMemory: 29275516928 AvailableVirtualMemory: 4105641984 BIOS_Manufacturer: Hewlett-Packard BlockedDllList: BreakpadReserveAddress: 91750400 BreakpadReserveSize: 41943040 BuildID: 20140716183446 CrashTime: 1406665003 FramePoisonBase: 00000000f0de0000 FramePoisonSize: 65536 InstallTime: 1406657909 ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release SecondsSinceLastCrash: 183 StartupTime: 1406665003 SystemMemoryUsePercentage: 14 Throttleable: 1 TotalPageFile: 39379963904 TotalPhysicalMemory: 34279690240 TotalVirtualMemory: 4294836224 URL: Vendor: Mozilla Version: 31.0 useragent_locale: en-US

This report also contains technical information about the state of the application when it crashed.

Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  http://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

No spyware detected. and I did try suspending my AV during install/launch.

Did the scans run to completion? Usually it takes a few hours to scan thoroughly. If the downloads behaved like trial versions and said you needed to pay, then please go to one of the specialized forums listed in our malware article for assistance because that indicates a serious problem: Troubleshoot Firefox issues caused by malware.

Clean Reinstall

A regular uninstall/reinstall may leave some stray files in your programs folder. This method is a bit cleaner.

(1) If needed, download a fresh installer for Firefox 30 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.)

(2) Exit out of Firefox.

(3) Rename the folder

C:\Program Files (x86)\Mozilla Firefox

to

C:\Program Files (x86)\OldFirefox

(4) Run the installer you downloaded in #1. It should automatically connect to your existing settings.

Does Firefox start?

Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders:

• C:\Program Files (x86)\OldFirefox\Plugins
• C:\Program Files (x86)\OldFirefox\browser\plugins

removing the folders and installing fixed the issue!

Thanks!

Hopefully they will stay clean.

Maybe you want to forget all about it, but if you wouldn't mind: could you compare the files in the new and old program folders to see what's different? You can use WinMerge (free/open source) from http://winmerge.org/ or your favorite file comparison program.

If you use WinMerge, you can capture the comparison results to a file or to the clipboard using Tools > Generate Report (check the checkbox to copy to the clipboard for pasting, in which case you do not need to give a file name).

Sorry, I just deleted the originals instead of renaming as I really didn't care about what was there.