Cursor blinks on my hp pc wen i start sometimes

your harddisk ned to fix error or virus infection.
when u poweer up the computer press F8 key then enter in safe mode.then type "cmd"in run then press enter.then u got cmd prompt.
then type"chkdsk /r" then press enter "y"
then restrt the pc.if your hardisk has error it fix with thisd process.if proble still remains your system is virus infected.scan your system with antivirus.