Bad Firmware
If you expirimented, or did otherwise, mess up your sansa, this might help. If it says something at startup, such as something or other about not reading the image and going into recovery mode, here's how to fix this. Turn off your sansa, switch the HOLD so it's locked. Press and hold the REC button, then, while holding REC, start it up. It will say to plug it into the usb. Do it. Then, a drive will appear on your computer. Open It. Go to this address: "http://www.sandisk.com/Retail/Default.aspx?CatID=1238". Download the firmware file that's right for your player model. Now, unzip to reveal the .mi4 file. Put it in the drive on your sansa. Now, unplug it and allow reset. There you go. That's fixed.
Pressed Too Many Buttons At Once
If you froze your sansa by hitting too many buttons at once, simply remove and replace battery.
NOTE TO ROCKBOX DEVS!!!
if you press and hold the center button, and then turn it on, it makes the turnwheel light up, and it's frozen. HOWEVER, plug it into usb and something will happen. Something About A TANGO blah blah blah PLATFORM. My computer needed drivers to install it. I didnt have em. So, help me out.
Oh, hows the progress on rockbox for sansa e200r series going?