I have downloaded windows xp3 .when I start a scan with spy bot search & destroy my pc shuts off. I also cannot get my pc to perform a restore point I am at my wits end can anyone help thx

Are you saying you downloaded "and installed" Xp sp3.
Because I don't know what XP3 is.
To go back to how things where go to Start-control panel-add and remove programs and remove SP3. I wouldn't
I would get rid of spy bot and try a different one as SP3 is good.
Try Superantispyware it's free