The first problem seems to me like the button cell battery on the motherboard is dead (Sometimes referred to as bios battery) so every time the machine is turned off the cmos (Bios) loses its setting's along with date and time.
The second problem you are recieving tells me the PC is old and therefore the hardware may not support the auto power off function in windows xp.
It may be that when you replace the battery (CR02 Button cell type) and furtherly set the bios up correctly, the power down function will work. If not the hardware may not support. Hope this helps.