Motorola Defy Plus - Apps are automatically closing few minutes after screen switches off This is driving me crazy.

I just bought a new Motorola Defy Plus (MB526) this week and plugged in a 16 GB SD card to it. Like the features it offered like Moto-Blur and all that. 

So after 2 days of use I dumped some songs to listen while traveling to office. I started the playlist (in Connected Music Player,i.e., the stock music player provided in defy plus) to listen to music. But after 30 seconds or so phone goes to standby and song continues. But before song duration is complete, the sound shuts off. If I check the phone there is no app running. I tried listening to radio, and it was same thing with radio as well. I thought it was some sleep timer problem in music player, but I did not find any settings to do so. I browsed for solution in many places in Internet. But could not find solution. I found similar problem for Android v2.2. But my phone has Android v2.3.6. In between I tried using other apps such as Live 365 and Remote for VLC. Live 365 felt like it ran for little longer but even that closed too. Same problem persisted for Remote for VLC also, i.e., it's active for a while. After 5-7 minutes or so the app has closed completely. 

Can I solve this problem by enabling Factory Reset? If I reset using that, I know that apps I installed will go away, and that is not a problem with me. But will the stock apps provided by Motorola go away too?

Sometimes I found the irritating Voice Command(I dont know what is called exactly, maybe - Listen app) window popping up. How should I turn that off?
Go to task manager icon from round lighted main icon at bottom center of phone. Once task manger is running , click on auto end list and remove your connect music app or any other app that plays music. Thats it.

Also notice before you do the operatino above that musics would stops playing after about 2 minutes. Because that is the default setting for the auto end list in the task manager app.