Look for these entries in your registry :

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run taskmgr.exe="%SYSTEM%\taskmgr.exe"

HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\
CurrentVersion\Run taskmgr.exe=%SYSTEM%\taskmgr.exe"

If they are there, I am positive it is : TROJ_JUNTADOR.G

It is related to the following Backdoor : BKDR_MIMIC.T

And it does the following :

The Trojan, TROJ_JUNTADOR.G, installs this backdoor (BKDR_MIMIC.T) as an Internet Relay Chat (mIRC) client. Unauthorized remote users may access machines infected with this malware through mIRC channels and then use them to launch a Distributed Denial of Service (DDoS) attack.