My first 16-bit computer was an Atari 520 STFM. ST is the model of the computer, F stands for internal floppy disk and the M stands for modulator, which allows the display output to be viewed on a TV using the analog aerial input.
This was a massive step up from 8-bit computers in terms of speed, memory, display and sound. The disk drive greatly increased the speed in which programs save and load. Many 8-bit computers already had most of these features but this was my first experience.
At first I mostly played games because I had to learn a different way to program in Basic. I had been used to turning on the Dragon to a Basic Interpreter but with the Atari ST I had to load a program from disk.
Upgrading the memory was not an easy job. There was space on the motherboard for additional memory. So I bought a kit of parts that contained new memory chips and de-coupling capacitors. I soldered these onto the mother board and after turning on my Atari I had 1048MB of memory!

The Mega STE in my opinion, is the best looking home computer ever produced (along with the TT). I bought mine by mail order and when it arrived I was really happy. The 40MB Hard disk spinning up and the noisy fan just adding to the excitement. However, there was an issue with it and it had to go back. When it returned the Floppy Disk was replaced with a 1.44MB High Density drive and the TOS had been upgraded to 2.06. A very happy outcome.
I upgraded the RAM to 4MB.
I replaced the Drive LED that had corroded. This is a common problem with the Mega STE.
I bought a UltraSatan Drive and internal cable kit. I created two mounting brackets to mount the UltraSatan in place of the internal 40MB drive that no longer works.

I have been given an Atari 1040 STE by my brother but it has a non-working floppy drive. At some point I need to replace or repair it.