According to several articles I found searching Google for MSA64CHK.DLL, the file is part of a spyware/adware dialer. You can probably remove the remnants of the dialer using Ad-Aware or Spybot. If not, you may need to download HijackThis, an analysis tool, and post the results in the Virus Information and Removal board.

See the second link listed below for details on how to obtain spyware/malware the removal tools you need.

Jim