FF 33.0 - I cannot remove avg isearch when open new tab.

Question

I have FF 33.0 installed and have a persistent problem with AVG isearch. I have tried all the help/forums but none have worked.
I have removed Google (via Manage Search Engines) and then click on Restore Defaults, close FF and restart, but AVG isearch re-appears when I open a new tab.
I do not have AVG installed (Windows 8) and isearch or AVG is not listed within Control Panel.
I am my wits end.
I have read that registry settings might be involved and/or also there is a "ghost" FF environment (kept when upgrading FF) that might be the source of the problem.

Answer 1

As requested, my troubleshooting information:
Application Basics
Name: Firefox
Version: 33.0
User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:33.0) Gecko/20100101 Firefox/33.0
Multiprocess Windows: 0/1
Crash Reports for the Last 3 Days
All Crash Reports
Extensions
Name: Copernic Desktop Search - Search Firefox content
Version: 3.7.0.8
Enabled: true
ID: {57319509-7821-41B0-9FDF-3B58F146AE33}
Name: McAfee Security Scan Plus
Version: 1.0
Enabled: false
ID: {e4f94d1e-2f53-401e-8885-681602c0ddd8}
Name: Skype Click to Call
Version: 7.3.16540.9015
Enabled: false
ID: {82AF8DCA-6DE9-405D-BD5E-43525BDAD38A}
Graphics
Adapter Description: AMD Radeon HD 7700 Series
Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Adapter RAM: 1024
ClearType Parameters: Gamma: 2200 Pixel Structure: R ClearType Level: 100 Enhanced Contrast: 400
Device ID: 0x683d
Direct2D Enabled: true
DirectWrite Enabled: true (6.2.9200.16581)
Driver Date: 3-28-2013
Driver Version: 12.104.0.0
GPU #2 Active: false
GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC)
Vendor ID: 0x1002
WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon HD 7700 Series Direct3D9Ex vs_3_0 ps_3_0)
windowLayerManagerRemote: true
AzureCanvasBackend: direct2d
AzureContentBackend: direct2d
AzureFallbackCanvasBackend: cairo
AzureSkiaAccelerated: 0
Important Modified Preferences
accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.capacity: 358400
browser.cache.disk.smart_size.first_run: false
browser.cache.disk.smart_size.use_old_max: false
browser.cache.frecency_experiment: 3
browser.places.smartBookmarksVersion: 7
browser.sessionstore.upgradeBackup.latestBuildID: 20141011015303
browser.startup.homepage_override.buildID: 20141011015303
browser.startup.homepage_override.mstone: 33.0
dom.mozApps.used: true
extensions.lastAppVersion: 33.0
gfx.direct3d.last_used_feature_level_idx: 0
media.gmp-gmpopenh264.lastUpdate: 1413757004
media.gmp-gmpopenh264.version: 1.1
media.gmp-manager.lastCheck: 1413969766
network.cookie.prefsMigrated: true
places.database.lastMaintenance: 1414056584
places.history.expiration.transient_current_max_pages: 104858
plugin.disable_full_page_plugin_for_types: application/pdf
plugin.importedState: true
privacy.sanitize.migrateFx3Prefs: true
storage.vacuum.last.index: 1
storage.vacuum.last.places.sqlite: 1413757479
Important Locked Preferences
JavaScript
Incremental GC: true
Accessibility
Activated: false
Prevent Accessibility: 0
Library Versions
NSPR
Expected minimum version: 4.10.7
Version in use: 4.10.7
NSS
Expected minimum version: 3.17.1 Basic ECC
Version in use: 3.17.1 Basic ECC
NSSSMIME
Expected minimum version: 3.17.1 Basic ECC
Version in use: 3.17.1 Basic ECC
NSSSSL
Expected minimum version: 3.17.1 Basic ECC
Version in use: 3.17.1 Basic ECC
NSSUTIL
Expected minimum version: 3.17.1
Version in use: 3.17.1
Experimental Features
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