aldan :
avast is one of the top rated avs out there.it has nothing to do with that.it may,or may not be malware.an av software is only part of any antimalware solution.it should be used in conjunction with other programs such as malwarebytes.to rule out malware do the following.download and run a scan with adwcleaner from bleeping computer.get rid of anything it comes up with and post the log in your next post.next,download and run a scan with junkware removal tool,also from bleeping computer.again,get rid of anything it comes up with and post the log.start there.there is no one program that will keep you malware free and that is where most make the mistake.
http://www.bleepingcomputer.com/download/adwcleaner/
http://www.bleepingcomputer.com/download/junkware-removal-tool/
ADWCLEANER
***** [ Services ] *****
***** [ Files / Folders ] *****
Folder Deleted : C:\ProgramData\Updater
Folder Deleted : C:\ProgramData\SearchDonkey
Folder Deleted : C:\Users\Daniel\AppData\Roaming\Mozilla\Firefox\Profiles\8hw4frby.default\Extensions\support@searchdonkeyapp.com
File Deleted : C:\Windows\SysWOW64\RegistryHelperLM.ocx
File Deleted : C:\Program Files (x86)\Mozilla Firefox\browser\searchplugins\avg-secure-search.xml
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxp_www.azlyrics.com_0.localstorage
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxp_www.azlyrics.com_0.localstorage-journal
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxp_services.hearstmags.com_0.localstorage-journal
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxp_services.hearstmags.com_0.localstorage
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxps_static.olark.com_0.localstorage-journal
File Deleted : C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Local Storage\hxxps_static.olark.com_0.localstorage
***** [ Scheduled tasks ] *****
***** [ Shortcuts ] *****
***** [ Registry ] *****
Key Deleted : HKLM\SOFTWARE\Classes\AppID\DynConIE.DLL
Key Deleted : HKLM\SOFTWARE\Classes\AppID\{384997EE-E3BE-49C4-9ECA-C62B7C08128A}
Key Deleted : HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{A92DAB39-4E2C-4304-9AB6-BC44E68B55E2}
Data Deleted : HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings [ProxyOverride] - *.local;<local>
***** [ Web browsers ] *****
-\\ Internet Explorer v10.0.9200.16686
-\\ Mozilla Firefox v25.0 (en-US)
[8hw4frby.default\prefs.js] - Line Deleted : user_pref("extensions.dynconff.cache.ca.msn.com.content", "<package expire=\"3600\" es=\"914\" pcdids=\"_1520_1659_1169_1916_1263_1482_1521_1717\">\r\n <content id=\"MB_P1\">\r\n <newjs><![CDATA[([...]
[8hw4frby.default\prefs.js] - Line Deleted : user_pref("extensions.dynconff.cache.members.elo-boost.net.content", "<package expire=\"3600\" es=\"914\" pcdids=\"_1520_1674_1169_1864_1916_1263_1482_1521_1717_1807\">\r\n <content id=\"MB_P1\">\r\n[...]
-\\ Google Chrome v41.0.2272.89
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://search.chatzum.com/?q={SearchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://search.chatzum.com/?q={SearchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://www.ask.com/web?q={searchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://isearch.avg.com/search?cid={515259C3-D125-47AB-AEB8-ED5E37EA3F97}&mid=142617d5eb0947d0932c19294656b5f6-6395d0fdabaddcc50312fb5c6cb4d49a2582878f&lang=en&ds=st011&pr=sa&d=2012-06-12 18:54:49&v=14.2.0.1&pid=avg&sg=&sap=dsp&q={searchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://asksearch.ask.com/redirect?client=cr&src=kw&tb=W3I4-G&o=41648001&itbv=11.5.0.834&doi=2013-02-14&locale=en_US&apn_uid=1DE51404-7976-4BC6-A9CF-FC0C4856EFC0&apn_ptnrs=^A9M&apn_dtid=^YYYYYY^YY^CA&apn_dbr=cr_24.0.1312.57&&q={searchTerms}
-\\ Chromium v
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://search.chatzum.com/?q={SearchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://search.chatzum.com/?q={SearchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://www.ask.com/web?q={searchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://isearch.avg.com/search?cid={515259C3-D125-47AB-AEB8-ED5E37EA3F97}&mid=142617d5eb0947d0932c19294656b5f6-6395d0fdabaddcc50312fb5c6cb4d49a2582878f&lang=en&ds=st011&pr=sa&d=2012-06-12 18:54:49&v=14.2.0.1&pid=avg&sg=&sap=dsp&q={searchTerms}
[C:\Users\Daniel\AppData\Local\Google\Chrome\User Data\Default\Web Data] - Deleted [Search Provider] : hxxp://asksearch.ask.com/redirect?client=cr&src=kw&tb=W3I4-G&o=41648001&itbv=11.5.0.834&doi=2013-02-14&locale=en_US&apn_uid=1DE51404-7976-4BC6-A9CF-FC0C4856EFC0&apn_ptnrs=^A9M&apn_dtid=^YYYYYY^YY^CA&apn_dbr=cr_24.0.1312.57&&q={searchTerms}
*************************
AdwCleaner[R0].txt - [6323 bytes] - [21/04/2014 18:04:52]
AdwCleaner[R1].txt - [4053 bytes] - [21/03/2015 02:21:10]
AdwCleaner[S0].txt - [6113 bytes] - [21/04/2014 18:08:34]
AdwCleaner[S1].txt - [5170 bytes] - [21/03/2015 02:24:47]
########## EOF - C:\AdwCleaner\AdwCleaner[S1].txt - [5229 bytes] ##########
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Junkware Removal Tool (JRT) by Thisisu
Version: 6.4.5 (03.17.2015:1)
OS: Windows 7 Home Premium x64
Ran by Daniel on 21/03/2015 at 2:29:05.37
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~ Services
~~~ Registry Values
~~~ Registry Keys
~~~ Files
~~~ Folders
~~~ FireFox
Emptied folder: C:\Users\Daniel\AppData\Roaming\mozilla\firefox\profiles\8hw4frby.default\minidumps [8 files]
~~~ Event Viewer Logs were cleared
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Scan was completed on 21/03/2015 at 2:33:18.57
End of JRT log
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~