Comodo firewall error

Hello, I'm new to this forum. I recently installed the free version of Comodo Firewall 2.4 for Windows 2000. It had been working fine up until yesterday. Basically, when I started up my computer, I would get a message informing me of an error. One of the messages read "An error has occurred while initializing the Comodo firewall". I would get the message any time I clicked on the desktop icon. I restarted the computer, and was able to get working for a while, but logging in this morning the message has returned. I tired to restart the computer, but it didn't work this time.

I'm a novice with computers, so it's a little hard for me to describe the problem. The other day, I had to post a problem over at the Avast forum, as I was not able to update my virus database. I told them about how much space was on the hard drive, and they told me I had very little space. So little, that they were surprised my PC was able to function. Since I have little experience with computers, I didn't really know how much ram was on my computer, or how much space I should have. My computer is second hand.

Can anyone help me out? Is there any reason why the firewall would run into errors? Sorry if my question is a little vague, but if anyone can offer help, it would be greatly appreciated! Thanks!