We present and discuss our findings on the identified causes for the differences of the results of two usability studies on the borrowed use of Gesture Therapy, a virtual rehabilitation tool for the cognitive stimulation and physical activation of elders. The studies focused on usability aspects including perceived usefulness, ease of use, intention of use and user experience. In the first study, we used self-report techniques to gather data, and found that previous technological experience had a significant effect on the perceived anxiety of elders; while on the second study, we used indirect observation techniques to gather data, and found that previous technological experience had a significant effect on the perceived enjoyment of elders. After a further analysis of the video recordings of the playing sessions, we identified that elders developed two different approaches to their using the application (explore-and-learn and score-and-compete), which could be related to their previous technological experience, and explain the identified differences. We observed that in the presence of problems, the response of participants was different depending on the adopted behavior. Based on this evidence, we distilled a set of preliminary guidelines to foster or inhibit certain behaviors and outcomes related to the effect of previous experience that were observed during our evaluation studies of virtual tools for the cognitive stimulation and physical activation of the elderly.