Where and how did you remove the 100mb of files? To see how much space you have used on your hdd in a terminal type:
You should see something like this:
This listing will give you a pretty good idea of how much free space you have .
Filesystem Size Used Avail Use% Mounted on
/dev/sda6 6.5G 3.8G 2.5G 61% /
varrun 992M 108K 992M 1% /var/run
varlock 992M 0 992M 0% /var/lock
udev 992M 96K 992M 1% /dev
devshm 992M 24K 992M 1% /dev/shm
lrm 992M 43M 950M 5% /lib/modules/2.6.24-19-generic/volatile
/dev/sda7 141G 68G 72G 49% /home
gvfs-fuse-daemon 6.5G 3.8G 2.5G 61% /home/jimk/.gvfs
/dev/sde1 2.0G 429M 1.5G 22% /media/disk
In this case I have a seperate root and home partitions. As you can see /dev/sda5 is my root partition and I've got 2.5G of available space. /dev/sda7 is my home partition and I have 72G of free space.