How to keep the Powerbook G4 1.5ghz alive?

if you are comfortable opening up the computer, then upgrade the hd. its somewhat long process. I did this surgery on my old school ibook a few years ago following the ifixit dot com guide and it worked!!! Unfortunately, i had like 4 screws left over but it didn't make a differences LOL. I'd definitely upgrade it. I think that ifixit website can give you product recommendations on the HD. pretty sure it does so at least you can upgrade the HD.

It comes down to how comfortable you are with taking apart your PB. Overall its not difficult if you follow the ifixit instructions. If its your first time make sure you go slow and try to keep track of all the screws.

I didn't notice anything when I upgraded my HD. Perhaps if u go with an ssd but that's out of your budget.

I'd try reinstalling the software and see if
that speeds things up a bit but again it's an old computer.

Basicly, to keep it running nice and fast you should only run programs on it that are recomended for your spec. Don't work with Photoshop CS4 etc, stick to older programs. You'll find that it works super fast at older programs that are meant to work with the specs.

If you need more space, get an external drive. You're only going to get a negligible performance increase from upgrading the internal drive. I doubt you'd even notice it.

External hard drive? lmao come on.

You can get a new PATA hard drive, I haven't seen one bigger than 320gb though. The install process is a bit of a pain, and you'll probably scratch your machine/leave permanent marks on it, but it is pretty old so no big deal right? Just be careful.

Go for a 7200rpm model if you can, if not find the fastest 5400rpm model (most cache, lowest seek times) - preferably a single platter drive. That'll help matters a ton.

If your ram is maxed, great! If not, consider getting it up to the max.

I'm typing this on a 1.5ghz myself

A new hard drive might help applications launch faster. But its not going to make youtube video's run smoother, or make photoshop render something faster.