Mdelk.exe is a malicious process that can download and execute additional spyware programs. We recomend to remove it using XoftSpy SE anti-spyware with free scan.

Mdelk.exe is actually an executable process that is the residual effect of downloading one of several worms and trojan viruses on the net today, some of which include Trojan.MitGlieder.GB and TROJ_MITGLIED.AA. The Mdelk.exe process is extremely harmful to your PC, can shut down most other processes and programs from running, including anti-spyware applications and internet access.
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Source: http://removal-tool.blogspot.com/2008/01/mdelkexe-removal-tool-remove-mdelkexe.html