The laptop has 1 or 2 GiB flashmemory which is devided in several blocks. One block contains the bootloader, another block contains the (linux-)kernel, and a third block contains 'the filesystem' which contains 'the distro'. (You could have seen this using 'cat /proc/mtd' when your laptop still worked)
The bootloader is executed first, on boot, and this loads and fires the kernel. The kernel mounts the filesystem and executes a script to fire 'the distro'.
The bootloader can be interrupted by a keycombo (ctrl-fn-f2, as I recall right) to flash another kernel in it's block. The kernel can be interrupted (f3) to write another distro to the filesystem.
So you rewrote the filesystem with Debian, but didn't touch the kernel or bootloader. F3 should still work. As long as you didn't do strange things (mkfs /dev/mtdblock1 or something like that) the kernel and bootloader should be fine.
You can try to reset the system. Use a paperclip or something like that on the small hole on the bottom. Additionally you can remove the batteries for a few hours.