I have a Q about formatting an old computer I have (windows ME), the problem is that when I turn on the computer, it detects an error immediatly after selecting the start up mode ( no matter what is it), and as soon as it detects the error, it turns off quickly, so I cant know what is the problem, so can somebody help me out with this prob

You need to use a bootable floppy.
As you still have access to a computer, use the following steps:
1. Insert a floppy into the drive
2. Go to My Computer
3. Right-Click on the Floppy Drive (probably A:)
4. Select format
5. Check the box for a MS-DOS Startup Disc (or similar).
6. Copy format.com (and any others which catch your eye, I'd suggest at least fdiskexe as well) onto the newly formatted startup disk. Format.com, Fdisk.exe and a number of other internal and external DOS commands can be found here.
7. Insert the disk into your PC and start it up.
8. At the DOS prompt type format /? . That will show you the parameters for the format command.

If you can't find the Startup disk option in step 5, the go to the command prompt and type (assuming the floppy drive is drive a) format a: /s