Erase HDD & Clear CMOS
Before doing the below routine ensure that you read our disclaimer as well as are sure that this is safe to do on your hard drive. Some computer hard drive manufacturers may void your warranty or this may cause damage to the hard drive when doing the below example. This routine is useful in clearing DDO and removing possible viruses. If this routine completes successfully it will erase everything from your Hard Drive as well as your reset your CMOS values. In the below debug routine, only type what is in bold from line 3 to 17, you will get a response if typed in properly. If you get a response continue to type the bold text as shown below in the below example.
-fcs:200 400 0
-xxxx:0100 mov ax, 0
-xxxx:0103 mov ax, cx
-xxxx:0105 out 70, al
-xxxx:0107 mov ax, 0
-xxxx:010a out 71,al
-xxxx:010c inc cx
-xxxx:010d cmp cx,100
-xxxx:0111 jb 103
-xxxx:0113 mov ax,302
-xxxx:0116 mov bx,200
-xxxx:0119 mov cx,1
-xxxx:011c mov dx,80

-xxxx:011f int 13
-xxxx:012l int 20
-xxxx:0123 (without typing anythhing.)
-g program terminated normally If you are doing this debug routine to clear out a possible virus turn off your computer and wait and turn back on.
Once back at DOS, reboot your computer When your computer comes back on from doing the above you will get an error message as booting up the computer, such as "Invalid Configuration". You must enter CMOS and set the time and date, save, and reboot again. Once rebooted, you will then need to run fdisk and recreate the partitions. Once created, you will then need to format the hard drive and proceed as normal.