I have also the same problem and I'm going crazy. When I read the log file in the adminsitrative tools it says the following message related with the error:
"The time service is now synchronizing the system time with the time source time.nist.gov (ntp.m|0x1|195.174.164.148:123->192.43.244.18:123)."
I have the latest version of norton antivirus with up- to- date virus definitions. I have scanned my drives but norton could not find any infected file and I'm sure that my computer doesn't contain msblast virus. Could you please help me.