Dell Dimension 4500S BSOD

Hi, I just wanted to know that the dell dimension 4500s, the old family computer, that after the xp bootup, it gave me the bsod:I will show you the message

STOP:c000021a  [Fatal System Error]

The Session Manager Initialization system process terminated unexpectedly with a

 status of 0xc0000034 (c0x00000000 c0x00000000)

can you please help me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!