New Tab opens to random websites every 15 minutes

Question

Here are the details of the random tab that opens every 15 minutes.
Application Basics
Name: Firefox
Version: 31.0
User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0
Crash Reports for the Last 3 Days
All Crash Reports (including 2 pending crashes in the given time range)
Extensions
Name: Adblock Plus
Version: 2.6.3
Enabled: true
ID: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}
Name: Block site
Version: 1.1.8
Enabled: true
ID: {dd3d7613-0246-469d-bc65-2a3cc1668adc}
Name: Strict Pop-up Blocker
Version: 0.1
Enabled: true
ID: jid1-P34HaABBBpOerQ@jetpack
Name: Troubleshooter
Version: 1.1a
Enabled: true
ID: [email protected]
Name: Wondershare Video Converter Ultimate
Version: 7.0.0
Enabled: false
ID: {8D150B8F-EFE8-45a3-A4A3-053020F48FAC}
Graphics
Adapter Description: AMD Radeon R7 240
Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Adapter RAM: 2048
Device ID: 0x6611
Direct2D Enabled: true
DirectWrite Enabled: true (6.3.9600.17111)
Driver Date: 9-10-2013
Driver Version: 13.152.1.1000
GPU #2 Active: false
GPU Accelerated Windows: 1/1 Direct3D 10
Vendor ID: 0x1002
WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon R7 240 Direct3D9Ex vs_3_0 ps_3_0)
windowLayerManagerRemote: false
AzureCanvasBackend: direct2d
AzureContentBackend: direct2d
AzureFallbackCanvasBackend: cairo
AzureSkiaAccelerated: 0
Important Modified Preferences
browser.cache.disk.capacity: 358400
browser.cache.disk.smart_size_cached_value: 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: 20140707160635
browser.startup.homepage: www.google.com.au
browser.startup.homepage_override.buildID: 20140707160635
browser.startup.homepage_override.mstone: 31.0
dom.mozApps.used: true
extensions.lastAppVersion: 31.0
gfx.direct3d.last_used_feature_level_idx: 0
network.cookie.prefsMigrated: true
places.database.lastMaintenance: 1404897208
places.history.expiration.transient_current_max_pages: 104858
plugin.disable_full_page_plugin_for_types: application/pdf
plugin.importedState: true
privacy.donottrackheader.enabled: true
privacy.sanitize.migrateFx3Prefs: true
privacy.sanitize.timeSpan: 4
storage.vacuum.last.index: 0
storage.vacuum.last.places.sqlite: 1404897208
JavaScript
Incremental GC: true
Accessibility
Activated: false
Prevent Accessibility: 0
Library Versions
NSPR
Expected minimum version: 4.10.6
Version in use: 4.10.6
NSS
Expected minimum version: 3.16.2 Basic ECC
Version in use: 3.16.2 Basic ECC
NSSSMIME
Expected minimum version: 3.16.2 Basic ECC
Version in use: 3.16.2 Basic ECC
NSSSSL
Expected minimum version: 3.16.2 Basic ECC
Version in use: 3.16.2 Basic ECC
NSSUTIL
Expected minimum version: 3.16.2
Version in use: 3.16.2
Experimental Features
Name: Search Experiment
ID: [email protected]
Description: Test alternate default search settings for users of Firefox beta.
Active: true
End Date: 1407398102966
Homepage:
I have scanned my pc with Mcafee and windows defender as well as Malware Bytes. I have also scanned my pc with Kaspersky TDSSKILLER and all found nothing wrong.
I am running windows 8.1
Other sites the random tab opens are: http://www.big-countries.com/canada.php
http://www.rich-countries.com/qatar.php
http://www.big-countries.pl/
http://www.rich-countries.net/switzerland.php
http://www.justin-bieber-best.pl/awards.php
http://www.big-countries.com/australia.php
http://www.big-countries.net/
http://www.rich-countries.com/switzerland.php
http://www.big-countries.pl/australia.php
http://www.rich-countries.com/germany.php
http://www.rich-countries.net/qatar.php
http://www.rich-countries.pl/germany.php
http://www.how-internet-works.com/sites_categorie.php

Answer 1

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.
You can try these free programs to scan for malware, which work with your existing antivirus software:
* [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner]
* [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware]
* [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller]
* [http://general-changelog-team.fr/en/downloads/viewdownload/20-outils-de-xplode/2-adwcleaner AdwCleaner] (for more info, see this [http://www.bleepingcomputer.com/download/adwcleaner/ alternate AdwCleaner download page])
* [http://www.surfright.nl/en/hitmanpro/ Hitman Pro]
* [http://www.eset.com/us/online-scanner/ ESET Online Scanner]
[http://windows.microsoft.com/MSE Microsoft Security Essentials] is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.
Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article.
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