I'm just curious as to what year that little notebook was made? My question has nothing to do with what type of O.S. to put on it, it's just me being curious.
As far as a non-Microsoft O.S. for your notebook, I'm a strong supporter of Ubuntu! I made the switch to Ubuntu little over a month ago and have never regretted it. Also there is a real "plus" with running with Ubuntu, it's uses very little system resources and I'm sure that it would work just fine with those limited resources you stated. If you did indeed decide to go with Ubuntu, please try and find yourself version 10.10, for 10.10 right now, from all I've read about 10.10 vs. 11.04, most are saying that 10.10 is the champion. To many bugs and fixes with version 11.04 right now, I'm holding off upgrading my version until 11.10 is released.
In regards to your RAM, I think 756 will due, for my primary computer loaded with 4 Gig's usually hangs out around 350MB to 500MB of RAM being used in a (lite) use and (idle) state. Also your video RAM of 64MB's should be fine, for on my (in home server) it's using a very old Nvidia GeForce 4200 Ti 128MB AGP video card, and for the most part it doesn't use up all resources on the card. You didn't state what power rating your old Intel Celeron processor is running at! But I suspect that it's in between 500MHz to maybe 800MHz, could be weaker, but that's just my best guess. If my "best guess" is right, than you will have no problem running Ubuntu 10.10!
My only serious recommendation that I'm going to give before I leave here, is that when you find version 10.10, look for their "notebook" version, I don't think their "desktop" version will do good for your little system.
Good luck to you and please have yourself a nice day!