I'v the same problem - dont see the AMD M82xt in device manager

to turn it off, kindly Use the Device manager and disable the device (Control panel > System > Hardware tab > Device Manager) by right clicking Imaging device and click Disable or type devmgmt.msc after you click run and you will be headed to device manager also... Even if you restart the laptop, it will not turn on the camera unless you enabled it from the device manager..

Take out the battery, memory, hard drive, and DVD drive. See:

http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-71461

for instructions.

With those items removed, connect the system to power and see if anything changes. If there is still no sound and no lights, the system needs to go in for service.

If you get some beeps, try adding one stick of memory back in. If there's no change, try the other stick (if you have one).

If the situation improves, start adding devices back one at a time.

go to device manager from the control panel, and then select " imaging devices" right click on the "webcam" and select the option "disable"

Maybe you need a new battery for your laptop Thinkpad t400; you can buy a 6-cell battery from http://www.aubatteries.com.au/laptop-batteries/lenovo-thinkpad-t400-series.htm
http://www.all-batteries.co.uk/notebook-batteries/lenovo-thinkpad-t400-series.htm
http://www.notebook-battery.org/notebook-batteries/lenovo-thinkpad-t400-series.htm

goto control panel > device manager > sound and audio devices and check for the device status.... if its not working properly the you need to reinstall the driver, this will fix the issue.... or please make sure that did you removed any windows components from add/remove programs.... if so, then do that again and enable all windows components, in that case it may ask you to insert the windows cd/dvd in the cd/dvd drive.....

Is the "broadcast-tower" light on (the leftmost icon on the lite-bar below the screen)? Have you got an available/working WiFi router? Have you been able to choose a network to connect to? My T400 works fine when all the above are enabled..

sound like you may have a bad battery charge board but let us pray that it is a separate baord that plugs into the mother board

You can go into the device manager on windows from the control panel and right click on the touch pad device listing. Then select disable this device. This will stop the touchpad from working until you re-enable it again.

Here is a pdf file of your service manual, make sure to save yourself a copy on your drive for future reference.

http://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/43y6629_04.pdf

Here is the ATI driver page on the Lenovo support site. They list the XP driver for your model. Download and reinstall to see if this solves your problem. If you get errors or if you are not running XP please post beneath this thread with additional info so I can follow up with you...