http://www.trendmicro.com/vinfo/virusencyclo/default2.asp?NAV=18&m=a&virus=&alt=&key=&payload=&type=Worm&day=&month=&year=&wkday= start there ... the thing you need to do most is get it out of your system registry
MANUAL REMOVAL INSTRUCTIONS
Terminating the Malware Program
This procedure terminates the running malware process from memory.
Open Windows Task Manager, press
CTRL+SHIFT+ESC, and click the Processes tab.
In the list of running programs, locate the process:
MSBLAST.EXE
Select the malware process, then press the End Process button.
To check if the malware process has been terminated, close Task Manager, and then open it again.
Close Task Manager.
Removing Autostart Entries from the Registry
Removing autostart entries from the registry prevents the malware from executing during startup.
Open Registry Editor. To do this, click Start>Run, type Regedit, then press Enter.
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>Software>Microsoft>
Windows>CurrentVersion>Run
In the right panel, locate and delete the entry:
"windows auto update" = MSBLAST.EXE
Close Registry Editor.
then scan your pc with a good AV program that has been updated for the different varients. also clean out all your temp files ect... the above link may lead to other tricks also good luck