That computer shipped with a Pentium 4 or Celeron, 256 or 512 MB RAM, and no graphics card. The latter means that you can take about 64 MB off the RAM, since that will be reserved for graphics use. The setup is similar to this computer, except that I have more RAM.
The first thing to do is to discover the RAM size. I would strongly advise you to get some more, whatever the answer is. You can get 1 GB of PC2700 RAM for about $10 or 8 at Amazon. If you install extra RAM, go to the BIOS editor and see if you can increase the amount of RAM allocated to video.
If you have 256 MB and don't add any more, you need Antix: that will run well on smaller and slower computers than yours. If you have 512 MB, then go for the MX version of AntiX. If you upgrade to 1 GB, then you have a much greater choice, but you don't want a flashy user-interface because you don't have hardware video acceleration. I'd recommend the Mate version of Mint.
All of those will come with a web-browser, email client, word-processor, media player, and graphics editor. For some idea of the extra software available