set your machine to boot up in runlevel 3. This can be done permenantly by editing your /etc/inittab file and changing the line
to
If you need to boot in runlevel 3 just once, you can do this temporarely changing your bootloader command line. This is how to do with grub.
- when grub displays "booting blabla in x seconds" press enter
- highlight your current kernel (should be default) and press 'e' (like edit)
- highlight the second line (kernel /vmlinuz-2.x.x etc...) and press 'e'
- go to the end of line and add ' 3' (space + three) and hit 'enter'
- press 'b' (like boot)
I don't see why you could not do the same thing with lilo but I don't use it so I don't know the exact command sequence.