請教

我的電腦一直反複啟動,但又無法進入WINDOWS界麵(WINDOWS XP);在安全模式下查毒,又沒有發現.請高手指點如何才能解決問題?到底是有病毒還是機器硬件故障?
屏幕上顯示:
stop:c000021a (fata,system error) the windows logon process system process terminated unexpectedly with a status of 0x0000005 (0x00000000,0x00000000)the system has been shut down
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