Fail to Load Windows XP Pro at start up

[Guest]

I recently replaced my hard drive in my notebook to a Western Digital 120
gig hard drive installed windows xp pro service pack 2 which I purchased a
new copy of, all the drivers, programs it is up and running however if I
don't power up the machine for a few days the screen goes to black and says
no operating system found I then push the power button again and windows will
load.

 

[Shenan Stanley]

I recently replaced my hard drive in my notebook to a Western
Digital 120 gig hard drive installed windows xp pro service pack 2
which I purchased a new copy of, all the drivers, programs it is up
and running however if I don't power up the machine for a few days
the screen goes to black and says no operating system found I then
push the power button again and windows will load.

Sounds like a bad cable/controller/connection.
Could also be weak power.
Could even be a bad hard disk drive.