I have received an email yesterday and It has an attachment. It gives me a message that the attached file has been blocked and ask me if I allow to show the file. I did not open the
attached file. Just sign out, and made a full scan to my machine using Avira anti virus, and
nothing was detected. Today I went to the same message and surprisingly I did not find
the attached file !! The file simply is not there !! How could you explain that ? What happened? and where did that file go ? What do you advice me to do now ?

I hope to hear from anybody very soon.

It would help if you told us which e-mail service you use, but considering the fact you received a message saying it was blocked it has most likely been deleted from the server.

I am using the yahoo. I don't know from where did I get that message which said that the file has been blocked , my machine or the firefox security tools. You know when you receive some files with photos, it will not show you the photos right a way, but just give you a yellow strip and tell you that the image has been blocked and give you an option if you would like to show or or not. Thats exactly what happen to me. I did not open the file and it was kept blocked by the system.

The thing is that I usually receive messages with blocked files
but those files would not be deleted. I mean I can go anytime and open them if I want. But the strange thing here is that I don't see the file it self . Why the server would delete this file in particular ?
The message is still not there, but just the file has disappeared.
What do you advice me to do ? Thanks

This is really a question for Yahoo as they may well of changed their policy on malware and virus detection and removal.

Ok, but what do you advice me to do now ? If I scan my machine using Avira and Ad-aware should my machine be fine ? Or it may still be at risk ?

If you didn't open the BLOCKED file then you have nothing to worry about.

I did not open it. It was trying to open, but just I told you it was blocked .. Thanks