Monitor failure at startup

My brother is using a compaq computer. during startup, during the transition state from the xp home loading screen to the login/select user page, the screen just died. although the cpu is still running, the monitor just entered sleep mode and refused to startup.

however in safe mode, all’s well and the moitor seems to be working alright.

i tried to reformat the computer, but the same scenario repeated itself.

help anyone?