check your startup folder maybe an exe file is set to launch during startup. Also check your registry: HKLM\Software\Microsoft\Windows\CurrentVersion\RUN |RUNOnce| RUN Services. Carefully check all entries regarding the program that launch during startup, you can then delete this entry, you may also check: HKCU\Software\Microsoft\Windows\CurrentVersion\Run
almost forgot, you may run MSCONFIG, check all entries there, you can then disable the program that launch during startup
