Why remove grub?

I am experimenting with a "half dead" harddisk and installed it with DOS and SUSE. Grub was installed by SUSE. After some testing, i decided to reformat and re-partition this harddisk.
After the reformating and re-partitioning, upon boot up, the system still ask for grub, so i need to learn how to remove it .


Question :
1. Am i right to assume that installing LILO will overwrite GRUB(if GRUB is previously installed) and vice versa?

2. If my harddisk has only windows now, can i still install LILO or GRUB to select booting by windows (after all this is the only OS left)?

3. If above is permissable, then i could install other distribution of Linux (including Knoppix) and configure GRUB/LILO to select the OS for booting up, right?

4. Anyone knows what is the default that Mandrake will load , LILO or GRUB.

5. I am having a WinME for family use and understand that I can (should, must) update to Win2K as the later is more stable.
a. Can anyone confirm it this is true.
b. How can I do the update without losing what inside my harddisk.


Thanks in advance for the info.