you can use debug. just boot up to a command prompt with a disc containing debug.

*** This will destroy all data on the hard drive! No kidding! **

--F 200 L1000 0 [ENTER]
--A CS:100 [ENTER]
xxxx:0100 MOV AX,301 [ENTER]
xxxx:0103 MOV BX,200 [ENTER]
xxxx:0106 MOV CX,1 [ENTER]
xxxx:0109 MOV DX,80 [ENTER] (Note: "80" is for hdd0, use "81" for hdd1)
xxxx:010C INT 13 [ENTER]
xxxx:010E INT 20 [ENTER]
xxxx:0110 [ENTER]
--G [ENTER]
Program terminated normally
--[CTRL] [ALT] [DEL]