If the Memorex is working as a player go to its Settings and see if there is a section about connecting to the PC -- if so try switching between MSC (or similar -- meaning removable drive) and MPT (or similar -- meaning sync with Media Player).

If you have the option to use MSC it will dave the hassle of dealing with Media Player -- the sync options on many MP3 players are clumsy and MSC means the player just appears as an extra disk drive allowing you to simply drag and drop your music files to load them to the player.