Duron was a very low end CPU. If it were a Pentium III or even an Athlon it would run better for more modern OS. With my experience with older same era CPU's XP will run nice on them until you add service packs and the over 100 updates. I have a Pentium III 600Mhz Laptop that I run at Windows XP Pro SP2 with 384MB Ram and it runs at a good speed at that. If I install SP3 and all updates it slows to a crawl. So I no longer use this laptop for anything that has to be secure or personal since I cant patch it to latest and have it still be a computer that is enjoyable to work with.
I tried a number of Linux Distros on the Pentium III 600Mhz with 384MB Ram and the biggest issue I found was that many of the modern distros call for 512MB Ram minimum with 1GB recommended such as Fedora, Mint, Ubuntu, etc. For a short while I ran my laptop on Fedora 5 and it ran at a good pace, but Fedora is now at version 17.
So my laptop no longer can run a modern GUI OS that is patched to the latest and still enjoyable, so I now use it as a beater to program on offline since Windows XP Pro SP2 still allows support for many modern apps which are no longer supported under the original Windows 98SE OS that my laptop originally came with.
*Personally Windows Me was one of the worst OS MS ever made. If you could find an Athlon CPU to upgrade to you would get better performance. You might be able to find one for less than $20 that would install into your system. Knowing what you have for a motherboard would help know what CPU's are compatible. Some boards you have to stick with the same CPU speed, so 750Mhz Athlon is the best choice, however if your motherboard supports faster, I'd go with the fastest available for your money if you want to invest in this computer vs retiring it. I had a eMachine once that was a 2.0Ghz Celeron, and the motherboard would not take a 2.4Ghz Pentium 4. I ended up having to stuff a 2.0Ghz Pentium 4 into it to squeeze out as much performance as I could out of it as for there was no BIOS flash to support any faster socket 478 CPUs. This eMachine was engineered with Planned Obsolescence in mind to install a motherboard that will only take 2.0Ghz socket 478 CPU's! I'd go with Windows XP, Athlon CPU 750Mhz or better if motherboard supports faster, get your Ram count to max of 512MB, unless your shared video is dropping you to the 448MB now, in which adding a video card can free up this Ram back to 512MB even if using a PCI graphics adapter if a AGP slot is unavailable. However if you dont already have the OS and hardware already, with excpetion to a $20 CPU upgrade you might be looking at wanting to invest the money into a new Motherboard, Ram, etc or completely new PC for like $349 for a low end new PC which would process way faster and be Windows 7 and more secure than a dated OS. Also if you want to play video games you will want to stick with Windows! I got games to run thru WINE, but they act up.