My file reads this, "multi(0)disk(0)rdisk(2)partition(1)\WINDOWS="My Bad Ass Machine" /fastdetect /NoExecute=OptOut" should it not say optin instead of optout?
Its to do with DEP(Data Execution Protection). Have a look at this http://technet.microsoft.com/en-us/sysinternals/bb963892.aspx .
take a look at this from MS site:
http://support.microsoft.com/kb/289022