EVZg3Kp2UG seems like a wierd folder, not a part of the default OS files.
Can you cd to it and see what is inside? You dont normally store anything to thr Root folder, do you? If anything then, I would delete it if nothing in it is yours. You only gained about a half of a GB then, but it should boot normally. I remember before I replaced my 40GB hdd that died (partially, wasnt detected by BIOS, only Linus or Windows) I was always trying to keep the free space down. I bought a 500GB USB HDD and moved the /home and Documents and Settings folders to it LOL.
Maybe you should consider getting a cheap 32GB flash for $16 or a 64GB flash drive for a little bit more and move old, and unused stuff to it. Funny how a cheap flash drive can exceed the size of a old HDD so easily.
I know this and what I am about to say probabally is a bad suggestion or out of the question, but have you considered a larger HDD once this is sorted out? If your MB supports SATA of any kind http://www.amazon.com/Western-Digita...ords=500GB+hdd is 500GB is on sale for only $60! If no SATA then, this thing http://www.amazon.com/HDE-SATA-Drive...7G0GK4W69Z5NZK allows you to connect a SATA HDD to a older motherboard using the IDE interface. I have a 2001 PC with a P4 also, but it does have sata, so chances are yours would too. HDDs have gotten much cheaper these days, and are pretty easy to get in larger sizes. For example, 3TB (3000GB) can be gotten for $150. That will be my next upgrade besides a P4 HT which is a dual threaded CPU.