Hi, Gloria. MRU (Most Recently Used) items are nothing more than lists of the most recent files accessed by various processes/programs on your system. For example, if you open any of the MS Office products they display a list of the last several files that were created/edited. These are normal system features and not the result of any malware. Some people consider these a privacy concern and clear them out. Others, like myself, appreciate the convenience that they offer and keep them. You can prevent Ad-Aware from reporting these by deselecting the "Search for negligible risk entries" switch in the Preparing System Scan pane which appears after you click the Scan now button.