LinuxQuestions.org - Fastest "switch on -to- ready to use" system for old laptops?

I was wondering if in this forum someone could show me the way... :)

I have an old laptop (Compaq Armada M700... a PIII with 576Mb RAM!!!) which I seldomly use. I have always "wished" I could use this old (and slow and crippled) laptop to do something basic, very basic: to connect to the Internet, browse my email, maybe download and read a PDF, watch some stupid Youtube videos (-not in HD, of course I know!)... and that's about it (no gaming, no Office, no Photoshoping, no anything else!). But I wanted to do that in style: fast and without hazzle -as 'in having to navigate thru somehow obscure prompt commands or similar!'.

I've tried installing a bare TinyXP... but yet it takes forever to start up, load... and be ready to navigate. I've also looked at the Linux world -albeit I am clueless on this OS- and I tried installing different flavours of Ubuntu and others. Unfortunately results weren't much better than with TinyXP -in regards of starting up and responding to user interaction in a reasonably and timely manner. Lately I've hear about the (in)famous Chrome or Chromium or whatever... but it seems it's not going to be ready for a while just yet and it won't necessarely work on such old laptops like mine.

Ah!... it HAS to be GUI-based... no command prompts!.

So...

Any suggestions on how can I rescue my old laptop to use it as explained above keeping in mind the hardware limitations I have?.

Any help would be certainly appreciated. I don't mind which OS to use providing I can EASILY install it in that laptop and that I can work with it within a couple of minutes of switching it on (max!)... anything else is of no use since I know I'd end up not turning it on ever.

Thanks a lot...
...and plz be considerated: albeit I'm a medium-advanced Windows' user... I'm no expert,... and I know nothing about LINUX :( so put your answers in plain and direct language.