Method (100; 200) for defending against cold-boot attacks on a computer in a self-service terminal, including the following steps, which are carried out by means of the main processor and system software configured for the system startup of the computer: - checking state data which are stored in a state memory (MEM*) to which the system software has access and which include at least two of the following state data items: - - first state data which indicate the period of time (t) in which the computer was without power since the last shutdown of the computer, in order to check (111; 211) whether the period of time (t) in which the computer was without power is less than a first parameter which defines a minimum period of time (t 0) which is required for clearing of the data stored in the main memory due to lack of power; - - second state data which indicate the temperature of the main processor in order to check (112; 212) whether the temperature of the main processor is less than a second parameter which defines a minimum temperature (T K) which is not undershot during normal operation of the main processor; - - third state data which indicate whether a housing in which the computer is installed has been opened; and/or - - fourth state data which indicate whether an external storage medium is used for the system startup of the computer which is not a component of the computer; wherein at least two of the state data items are checked (111; 112) in order to determine deviations from parameters (t 0, T k) which are defined for a normal state of the computer; - if deviations from the parameters (t 0, T K) are determined for at least two of the checked state data items, at least subareas of the volatile main memory are cleared or overwritten; otherwise, the volatile main memory is not cleared or overwritten; - then, the system startup of the computer is carried out by means of the configured system software. - checking state data which are stored in a state memory (MEM*) to which the system software has access and which include at least two of the following state data items: - - first state data which indicate the period of time (t) in which the computer was without power since the last shutdown of the computer, in order to check (111; 211) whether the period of time (t) in which the computer was without power is less than a first parameter which defines a minimum period of time (t 0) which is required for clearing of the data stored in the main memory due to lack of power; - - second state data which indicate the temperature of the main processor in order to check (112; 212) whether the temperature of the main processor is less than a second parameter which defines a minimum temperature (T K) which is not undershot during normal operation of the main processor; - - third state data which indicate whether a housing in which the computer is installed has been opened; and/or - - fourth state data which indicate whether an external storage medium is used for the system startup of the computer which is not a component of the computer; - - first state data which indicate the period of time (t) in which the computer was without power since the last shutdown of the computer, in order to check (111; 211) whether the period of time (t) in which the computer was without power is less than a first parameter which defines a minimum period of time (t 0) which is required for clearing of the data stored in the main memory due to lack of power; - - second state data which indicate the temperature of the main processor in order to check (112; 212) whether the temperature of the main processor is less than a second parameter which defines a minimum temperature (T K) which is not undershot during normal operation of the main processor; - - third state data which indicate whether a housing in which the computer is installed has been opened; and/or - - fourth state data which indicate whether an external storage medium is used for the system startup of the computer which is not a component of the computer; - if deviations from the parameters (t 0, T K) are determined for at least two of the checked state data items, at least subareas of the volatile main memory are cleared or overwritten; otherwise, the volatile main memory is not cleared or overwritten; - then, the system startup of the computer is carried out by means of the configured system software.