Question : Problem: Power Cord Error Message

Daughter has Dell Laptop, approx 3 yrs old.  uses  -- school and social
Was receiving error message that adpater cord was invalid, (Error Code 3600:0649 Msg: invalid AC adapter reported). In additiona she is noow receiving message that her battery is no longer usable.
This is the same plug that came with her laptop and was fine until 2 months ago.

Answer : Problem: Power Cord Error Message

i think you have a problem with the battery, the adapter, or the loading circuits in the laptop.
try to eliminate each, by using another one

you don't loose data with a system restore : http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/systemrestore.mspx