u mean it was starting before and now it is not booting anymore

yes, that s right. I have been using it for a week without any problem but now it starts and starts and starts again. and it gives this:
"a problem has been detected and windows has been shut down to prevent damage to your computer." It ofrfers me to restart, when I resatart I meet this again.

Reinstall the os -- you DO have the original CD don't you? When you start the cd it will probably ask you if you want to repair the current installation.

how can ı attach a video here? i will show you what happens when ı use cd

make sure the first boot device is the CD and then boot...

when I press F12 this screen is shown:
2. IDE CD: HL-DT-ST DVD RAM GSA_T
3.IDE HDD: WDC WD1600BEVS_22RST0
7.PCI BEV: B02 D00 YUKON PXE

enter set up. ı put th dvd, mark IDE CD and say enter,
but the screeen says loading files and then says
"a problem has been detected and windows has been shut down to prevent damage to your computer." It ofrfers me to restart, when I resatart I meet this again.

looks there is a problem in the hardware u could check the cd-drive cables
and the HDD cables

Thanks a lot for your patience and help.

But I thing I cant check the cables as it is a notebook and I dont know enough about cheking them in a notebook

do you have any more offer sir, please