11421604.exe is an alternative name for the PLAY_MP3 trojan. This executable file is downloaded from a website which promises the user a free .MP3 or .MPG player.

Spreading through peer-to-peer file sharing networks, users download files (going by a variety of names) which are disguised as MP3s or MPGs. Instead of sharing music or video these files simply direct the user to a web page from where, they are promised, they can download a free media player.

They will then install the PLAY_MP3.EXE executable, which, when run, installs the Downloader-UA.h downloader. Oddly the user is also shown, and asked to accept, a lengthy license agreement permitting the installation of the adware programs "SurfingEnhancer" and "FBrowsingAdvisor" onto the user`s PC.

Once installed the PLAY_MP3.EXE file can perform a number of malicious activities including displaying adware, installing unwanted programs, hijacking the user`s system and communicating with third parties. The promised media player then turns out to be a web-based player which offers only a limited range of saved tracks.

As a note on naming, trojans may have different versions of themselves, each with a different name and possibly slightly different behavior. These various versions are called strains, and trojans and their strains can also be grouped into families. Play_MP3.exe (and its over 220 alternatively named strains) are part of Downloader-UA.h downloader, Trojan.AdClicker, and Adware Generic2.AARK families.
Non-system processes like 11421604.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues.

Warning! 11421604.exe is considered to be a dangerous process and should be removed. Running unused processes can increase the risk of malware infection if bugs are present. Check your computer for viruses or other malware infected files.

This process is not considered CPU intensive. However, running too many processes on your system may affect your PC’s performance. To reduce system overload, you can use the Microsoft System Configuration Utility to manually find and disable processes that launch upon start-up. Alternatively, download SpeedUpMyPC to automatically scan and identify any unused processes.