This trojan allows a hacker to remotely take control of the infected computer. It copies itself as 'SYNCHOST.EXE' into the C:\%Windir% directory and hooks the following registry key:
With the value: "Remote Access Slave" C:\%windir%\Synchost.exe
By modifying the registry in this way it allows itself to execute after every time the computer is re-started.
The trojan also opens port 4999 to allow the hacker access to the infected computer.
Seems you need to do a trojan / antivirus scan pretty soon.