I've at times had similar problems on my wife's machine which has a dvd drive rather than a cdrom drive. Curiously, if I copied all the files from the cd to a temporary directory on the hard disk I could then install from those copies. The only problem is that some software tracks the source of the installation files. In such cases you must track down the ini file or registry entries to change the source back to the cd drive rather than the temporary hard disk files. It might be worth trying this before you reformat your hard disk.