Based on the results in the screenshot, the search is just returning results for "bios". It certainly looks like your MySQL server has its minimum word length set to 4. If you decrease the option within XF but don't change the MySQL setting, you will mostly just get words being silently ignored from your search. Out of the box (4 in XF settings and MySQL), there would be a message that indicates that "hp" and "541" were not included in your search.