269758 Detecting malware in EXE file

We have custom developed exe file for which the source codes are missing. We suspect that the former programmer may have put in a time bomb (making the program not working after a time lapse or after so many executions), or may have implanted malware to damage the system. Can you detect such problems in our exe file or fix it. (we will need to develop the program again, but we do not have the time to do so at this point.)