how to restart computer after a disc read error, ?

This seems as if the settings for your hard drive are not set in the bios.

Go into your bios and use the autodetect feature which should then give the manufacturer and capacity for the hard disk, if it doesn't have it check the connections on the hard disk, obviously the hard disk should be set as a master,then try booting.

Another problem which can occur is that the FAT32 or NTFS partition has been damaged and this will mean that you will have to boot from a bootable CD which has the OS on and install it, I have had this problem which solved it.

Hope this helps mate, let me know how you get on

Kenno
November 2010