> I did not expect much, and because the bottlenecks were the HDD and CPU I did not feel any noticeable performance improvement. Still, it occurred to me that it might be fun to take the netbook completely apart and start replacing its hardware piece by piece.

I would look at swapping out the HDD for something solid state - lighter, less power, higher performance for random R/W.

Then it's just a case of lightening the load of the CPU as much as possible, strip out everything that is not needed.

I've run modern Firefox on much lighter devices. One of my netbooks is the same spec as this, and I do browsing + coding on it easily.