To resolve the issue of new memory modules not being recognized, the systems administrator should configure appropriate settings within the BIOS. This can include enabling memory mapping or setting memory speed and timings. References: CompTIA A+ Certification Exam Objectives, 220-1001 Section 1.8

Configure appropriate settings within the BIOS. If new memory modules were installed in several Windows desktops but some users are still reporting performance issues and the desktop has not recognized the new memory modules, the systems administrator should configure appropriate settings within the BIOS to help resolve this issue.