volant: maybe problem is between keyboard and chair.... I´m joking...sometimes the reason why this or that have happened to Windows are...hmmmm....let´s say inexplicable . Really this should be happened by any other applications you have installed into your computer or this might be indication that your computer have been infected by some spyware,adware,virus or something like that from net.
I have some experiences with system restioration too, and after 2 or 3 months it didn´t work good as you wrote.I think this is not good way to backup your system. Maybe you can try NortonGhost or other applications that are hundred times better and works very good. It is a shareware but I am sure that there can be found any other freeware programs that will be able to satisfy your needs.
Try google it.