Unable to download any .exe file! Downloaded .exe files disappears! After download the .exe files gets deleted automatically! Virus Infection? Antivirus application is not scanning the computer?

Symptoms

Some of the related Symptoms of the problems are as under:

1. Web-browser downloads the .exe files. Progress bar shows download progress, but when reaches 100 %, the downloaded .exe files disappears.
2. In Windows 7/Vista/XP based computer.
3.  Windows asks for check-disk (chkdsk) on every boot.    
4.  Antivirus Application for example: AVG shows updated virus definition would not scan the computer.

Solution

The system is possibly infected with Virus/Trojan/Spyware. There is a very good  spyware and malware removal program Spybot Search & Destroy (S&D) compatible with Microsoft Windows. It scans the computer hard disk and/or RAM for malicious software. It can be downloaded from http://www.safer-networking.org/en/spybotsd/index.html . It can also directly be installed/run from a removable media CD/DVD/USB/Flash drive ( http://forums.spybot.info/archive/index.php/t-3191.html).

Snap  given below shows a Trojan detected below by Spybot-S&D: