Win 7 ,what happend?

First, you need to see if malware is affecting your system, download the free version of this;

Malwarebytes

and run a FULL scan after updating the database. If it finds anything, post the log here.

I realise you may have difficulty if you are unable to access the internet from the machine with the problem. You can download to your laptop, and then copy the installation file to your desktop.

Regards....Mike Connor

Alfons said:

Downloaded, scanned and clean .

Seems I'm missin the dnsapi.dll file which I've now been trying to get back in my system. I believe my problem to be that the dnsapi.dll files I've downloaded aren't compatible with my win 7 x 64 client. *facepalm*

Any tips?

Well, I'm afraid the only sensible advice on that, is not to do it, most of the things on line associated with this dnsapi business are scams of some sort.

The dnsapi.dll is not essential to Windows 7 and I would advise you not to download anything like that from anywhere. If you have already done so, run a malware scan and delete them.

My best guess right now is that you have some form of trojan etc on your machine. These are known to disable anti-virus software.

Download this and run it;

SUPERAntiSpyware.com | Remove Malware | Remove Spyware - AntiMalware, AntiSpyware, AntiAdware!

You should also run this to check your system files;

SFC /SCANNOW Command - System File Checker

If those things don't work, then I think you need to consult one of our resident security experts and do some deeper scans and investigation.

Regards....Mike Connor

Not sure just what you mean by the comment "You'd be better to run the Avast install program to repair broken or missing dll files." What does Avast have to do with this problem. Running sfc /scannow is the preferred way to replace broken/missing Windows files. Sorry if I am missing something here.

Regards
JohnnyA

johnnya said:

Not sure just what you mean by the comment "You'd be better to run the Avast install program to repair broken or missing dll files." What does Avast have to do with this problem. Running sfc /scannow is the preferred way to replace broken/missing Windows files. Sorry if I am missing something here.

Regards
JohnnyA

I think he just made a mistake. No harm done.

Regards....Mike Connor

wazzam said:

I was assuming that the missing dll was file needed by Avast after the OP said "avast (antivirus) couldn't start up since some dll file was missing".

No problem. However, anything that disables an anti-virus program is almost certainly malware. There are huge numbers of Internet scams which rely on the victim downloading some file or other which sounds as if it should belong to the operating system. This is NEVER the case.

You should NEVER download anything like this.

The way to check system files is by using;

SFC /SCANNOW Command - System File Checker

You have to be very careful when giving advice, because if you give the wrong advice you can destroy somebody's system, and cause them a lot of problems.

Quite a few people will automatically assume that any advice they see here is OK. This is quite a heavy responsibility for all of us.

Anybody can make a mistake, and we all do! But if you are unsure about something it is better to ask about it, or say nothing.

Regards....Mike Connor