Can´t update via windows update

hi there:)
have a read of this link (the quote is a extract from it) >>> Windows Update errors – A troubleshooting guide - 4sysops

Download the Windows Update Agent (WUA)

As a Windows component, the Windows Update Agent (WUA) is also updated through Windows Update. But if Windows Update errors occur, you should check if you really have the latest version. You can determine the WUA version by checking the properties of wuaueng.dll in %SystemRoot%\system32\. As of this writing, the current file version is 7.5.7601.17514 for Windows 7 and 7.4.7600.226 for Windows Vista and Windows XP. If you don’t have the latest WUA version, you can download the Windows Update Agent here and then install it manually. Even if your Windows Update Agent is up to date, you could check out whether reinstalling WUA solves your problem.

Several of the rogue programs out there will disable Windows Updates. Was your computer recently infected?

Give this a try:

Go to Start, Run and type or Copy/Paste the following line:

Code:

 %SYSTEMROOT%\SYSTEM32\REGSVR32.EXE   %SYSTEMROOT%\SYSTEM32\WUAUENG.DLL

Hit Enter

I think you should scan your computer for malware.

Please download Malwarebytes' Anti-Malware and save to your desktop.

• Right-click mbam-setup.exe And select " Run as administrator " then follow the prompts to install the program.
• At the end, be sure a checkmark is placed next to:
  Update Malwarebytes' Anti-Malware
  Launch Malwarebytes' Anti-Malware
• Then click Finish.
• If an update is found, it will download and install the latest version.
• Once the program has loaded, select Perform Full Scan, then click Scan.
• When the scan is complete, click OK, then Show Results to view the results.
• Check all items except items in the C:\System Volume Information folder... and click Remove Selected.
  Note: If MBAM encounters a file that is difficult to remove, you will be presented with 1 of 2 prompts, click OK to either and let MBAM proceed with the disinfection process, if asked to restart the computer, please do so immediately. Failure to reboot will prevent MBAM from removing all the malware.
• When completed, a log will open in Notepad. Please copy and paste the log back into your next reply
• The log can also be found here:
  C:\Documents and Settings\Username\Application Data\Malwarebytes\Malwarebytes' Anti-Malware\Logs\mbam-log-date (time).txt

Because you were infected with this Bot ... Backdoor.Agent.PS
You need to change all of your passwords, using a 'known clean' computer. Don't use the one that was infected!
ThreatExpert Report: Trojan.PR.Agent.PS, Backdoor.Trojan, Trojan-Proxy.Win32.Agent.ex..


Also, Download the HostsXpert 4.3 - Hosts File Manager. This will restore MS's Hosts file.

• Unzip HostsXpert 4.3 - Hosts File Manager to a convenient folder such as C:\HostsXpert
• Click HostsXpert.exe to Run HostsXpert 4.3 - Hosts File Manager from its new home
• Click "Make Hosts Writable?" in the upper right corner (If available).
• Click Restore Microsoft's Hosts file and then click OK.
• Click the X to exit the program.
• Note: If you were using a custom Hosts file you will need to replace any of those entries yourself.

To the OP. What you haven't solved is how did you get all this shhhhit. To make sure it's does not happen again. IMHO that might be the next thing to look at.