The possibility of an electromagnetic (EM) side channel attack on computers has been known since 1967. Each executed instruction/event from running a program on a computer/laptop causes an EM signal at particular frequency. Based on this signal, theoretically, it can be established what is happening on the computer/laptop. In practice, no one has used EM leakage to decode instructions in detail or extract full information from memories if computers work internally without exchanging information with the outside world, e.g., through the Internet, etc. The main focus of this research is determination of the EM leakage from a modern laptop. Three main experimental components that help to detect the leakage are addressed: a spectrum analyzer (SA), a tracking generator, and "victim" laptop (the one which leakage is measured). All of the research on the EM side channel attack used EM far-field probes. EM near-field probes have been applied to this EM leakage for the first time. Studying the characteristics of the leakage spectra from a laptop could lead to new protection techniques and improvements for laptop-safe instruction executions. EM data were collected in varying frequency bands, environment conditions, and running programs. A cache hit/miss program was chosen for testing the possibility of the EM leakage because of the highest radiation level compared with other instructions. The program was written in such a way that allows to specify and change the program’s frequency. This frequency was successfully detected in this study.