when i removed windows and try to install new windows xp i get this error (invalid system disk) and try to install it in dos prompt error (fail on int 24) appearSounds like an ancient machine to me...On computers old or new, MS-DOS INT 24 error MEANS a CRITICAL error has occurred, probably failure to write to disk. It is usually followed by the prompt (ABORT, RETRY, IGNORE). Possible causes: Hardware failure (hard disk drive or controller), hard disk cable faulty or loose, hard disk incorrectly partitioned. Other possibilty: ancient (reported 1992) MS-DOS virus ("Green JOKER") has infested every .com file in MS-DOS boot media. This is less likely given that the Windows installer also fails.


I know I'm many years late to the party here, but I had this INT 24 problem with my 5 1/4 drive.

I tried different floppy cables, different 5 1/4 drives, disabling drivers. It drove me crazy for hours. The one thing I didn't change? The actual floppy disk.

Once I found a 5 1/4 floppy disk which actually worked, the "fail on INT 24" problem went away.

Hope this HELPS someone.