You "Boot" the System from an Installation Disk (Usually a CD or DVD), and foolow the directions VERY CAREFULLY. You may lose all the data on the current installation Hard Drive if you make the wrong choices.
If you operating system is unbootable, then the safest option is to reformat and reinstall.
if you formatted it no, you would have to reinstall the old OS again
recovery
Reinstall the operating system.
Recovery ~tekno
Use system restore, failing that reinstall M.E.
Reinstall your operating system. You can't set it, but it will change.
You will need to reinstall the operating system.
you have to use the same product key..
Cd and DVD are auto detect by operating system.
Try with pressing F8 whilst starting up.
"Hidden" is a file attribute; this is information about the file that shouldn't change when you reinstall the operating system.