In the past fews days i've had a problem with Avast, with Action Center saying that there wasn't any protections programs running (can't describe exactly the message, but in general said Avast wasn't activated, even when, actually, it was). After that, tried to deactivate Avast and activate Windows Defender, but everytime i try to turn it on, the computer opens the system32 folder. I've tried the solutions already said about it, but with no effect. When i try to activate it on services.msc, it says it doesn't have a digital signature. Tried sfc /scannow, but the only message i received was that there was problems that couldn't be corrected. Also used the Avast removal tool, but with no effect. I'd like to know if there is something i can do before trying the 'reset'. Thanks. Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question. If sfc /scannow detected a problem that could not be repaired, then a refresh may be in order, or potentially a reset. First see if anything in this thread helps: http://answers.microsoft.com/en-us/protect/forum/protect_defender-protect_start/windows-defender-wont-start-in-windows-8-after-a/c5fdc22d-3b62-44cc-8485-4a3955b8985a It is entirely possible that malware got past Avast and has damaged the system preventing Defender from running and even Avast, although it appeared to be running before you removed it. Try Hitman Pro Trial Version: http://www.surfright.nl/en/hitmanpro This program may be run from a flash drive. Try TDSS Killer: http://www.bleepingcomputer.com/virus-removal/remove-tdss-tdl3-alureon-rootkit-using-tdsskiller TDSS Killer may be run from a flash drive. You may wish to download (on an uninfected PC) one or more of the following rescue scanners to create bootable media to scan the infected PC (list courtesy of forum member, GreginMich): http://windows.microsoft.com/en-US/windows/what-is-windows-defender-offline http://support.kaspersky.com/us/viruses/rescuedisk http://www.f-secure.com/en\_EMEA-Labs/security-threats/tools/rescue-cd/ http://www.bitdefender.com/support/How-to-create-a-BitDefender-Rescue-CD-627.html http://www.avira.com/en/support-download-avira-antivir-rescue-system http://www.avg.com/us-en/avg-rescue-cd-download http://www.freedrweb.com/livecd/ http://www.superantispyware.com/portablescanner.html http://support.kaspersky.com/faq/?qid=208283363

http://www.eset.com/int/download/utilities/detail/family/239/ Each rescue scanner will miss things – because none of them will have a perfectly complete and up-to-date set of definitions; so you might need to use several of these rescue scanners, or something like the Shardana Antivirus Rescue Disk Utility, which creates a custom bootable CD or flash drive that includes multiple rescue scanners: http://www.sarducd.it/ -- be sure to decline all of the additional junk being offered when you install the download for SARDU. I tested this install recently and the first offer was for the hated and difficult to remove Delta Search Toolbar. Another boot CD (similar to Shardana) to consider is Hiren's Boot CD . You can also start here - https://support.microsoftsecurityessentials.com/ and select the link that says - I think my computer is infected. Options will vary by region, but phone support leads you to Microsoft Answer Desk ( http://www.answerdesk.com/ ) in the US at this time. After an initial free consultation, a fee will be charged for assistance, based on the details of the case. This web site - http://www.bleepingcomputer.com - contains details for many of the common infections, often immediately after they began to appear in the wild, and instructions are provided for how to remove the infections using their malware removal guides. They also have forums where you can seek help from people who specialize in malware removal. This may also be helpful - How to get rid of malware: http://answers.microsoft.com/en-us/windows/forum/windows_vista-security/how-to-get-rid-of-malware/ba80504b-61f1-4d71-960f-b561798b7b42 Personally, I'd simply go right to the reset, assuming you've backed up your important data. http://windows.microsoft.com/en-US/windows-8/restore-refresh-reset-pc 2 additional answers Anonymous 2014-07-27T15:43:37+00:00 Thank you for the update. Yes, I presume that the issues were related to the same system corruption. -steve 0 comments No comments Thank you for the update. Yes, I presume that the issues were related to the same system corruption. Anonymous 2014-07-26T06:13:28+00:00 ~ First, sorry for the delay in replying, I ended up getting busy with school projects. ~ Well, I tried Hitman Pro and TDSS Killer, running them from a flash drive, but nothing changed. The scanners also didn't help, neither all the articles. So I decided to stop looking for the problem and go directly to the refresh or the reset options, but now I face a new one: neither of them work, just sending a message like "Problem on restoring PC. No changes were made". So, now I can't even reset or refresh the system. edit - Presuming that the same problem that is not allowing me to run Defender is the same that is not allowing me to reset or refresh the system, or something like this, tried to refresh in the advanced initialization, and, finally, it worked. Still don`t know what caused it, but for now Defender is working again. Thanks for your support. xD 0 comments No comments ~ First, sorry for the delay in replying, I ended up getting busy with school projects. ~ Well, I tried Hitman Pro and TDSS Killer, running them from a flash drive, but nothing changed. The scanners also didn't help, neither all the articles. So I decided to stop looking for the problem and go directly to the refresh or the reset options, but now I face a new one: neither of them work, just sending a message like "Problem on restoring PC. No changes were made". So, now I can't even reset or refresh the system. Presuming that the same problem that is not allowing me to run Defender is the same that is not allowing me to reset or refresh the system, or something like this, tried to refresh in the advanced initialization, and, finally, it worked. Still don`t know what caused it, but for now Defender is working again. Thanks for your support. xD