Do you know the specs of this laptop off hand? 2007 would place it in sort of a grey area between 32 bit and 64 bit CPUs. If it is 32-bit, you are likely going to have major issues and I would recommend using something else.

Even if it is a 64-bit CPU, the performance may not be amazing, and running modern browsers with anything less than, say, 4GB RAM could be an issue.

I would recommend something lightweight, such as Linux Mint with the XFCE Desktop Environment. You may need to get even more aggressive about finding something lightweight for something that old, though.

I have been using KDE on Arch across several machines for about 3 years now, then Manjaro for a year before that. At no point have I experienced instability or issues like that. Especially that last one; I’m the sort of person who regularly has 10+ tabs open on laptops with a fraction the amount of RAM that you have.

I would say that is definitely not normal. If that happened to me, I might search online or check journalctl -b -p 3 to see if it yields any clues.