Unstable Dell Studio 1537

Friends,
1) I have Dell studio 1537 with windows xp ? sp3
I noticed that sometimes my integrated webcam works well and sometimes not?..sometimes work with the integrated Mic and sometimes work without it,
Do you know how to solve this issue, may be you have the right driver

2) Another very strange issue,
Sometimes when I move my laptop from its? place I hear a sound from the laptop like the sound of plug-in and unplug USB connection!!!!!!!!!!!!!!
That?s too strange and too silly while It didn?t affect my work and didn?t create any problems

3) The last issue, there a lot of options in the motherboard regarding USB, etc what?s the best configuration of it as I changed some of it like SATA mode (I changed it to IDE mode to install windows XP)