AutoCAD 2012 crashes at start up on an XP 32 bit machine

Hello experts,
I am using Windows XP. I have installed an Autodesk 2012 on it.
Also,it was running very well upon first set up but then without any clear reason, I saw some crashed when I was opening the software. Then I got the following error message. Please help me to solve this.
Thanks in advance.

AutoCAD Application
AutoCAD Application has encountered a problem and needs to close. We
are sorry for the inconvenience.
If you were in the middle of something, the information you were working on might be lost.
Close
