My days of always trying to solve the presenting problem by taking deep dives "under the hood," with no guarantee that those will yield fruit, are over.
The world is different than it was back then. Reinstalling Windows 98 from scratch, backing up and restoring all those programs, dealing with driver issues, etc. was a huge pain in the butt that could literally take all day. It was worth investing an hour or two to try and "fix" the issue with the operating system. I can load a Windows 10 image on an SSD in literally 5 minutes. Unless they've got EXPENSIVE software that can't be replaced, I'm re-imaging the system after backing up the important data.
Now it's about fixing what's broken with maximum speed and minimal cost.
This is my goal as well. I might charge a lot of money for my services, but that just means that doing things quickly is even more important. Most systems I spend 30-60 minutes on and I make an average of $370 or close to it (I'm too lazy to look it up right now). I'm not going to spend 2-3 hours on a system without charging 2-3x my hourly average. Doing so would be stupid. I replaced a DC jack on a Dell laptop today. Charged $350. Part cost me $11. Took about 30 minutes including interacting with the client, ordering the part, and installing it.
I'm not going to muck around in Windows for 2 hours trying to find rootkits or trying to fix the start menu unless someone is paying me at LEAST $500 for it. It's cheaper for me to spend 30 minutes re-imaging their system and getting them an SSD upgrade for $350, and they end up with a better computer in the end.
That's a big part of the reason I will not do anything that takes more than 5 minutes, max, as far as fixing issues with unsupported software.
I actually spent 2 hours trying to get the Adobe CS6 master suite to work with High Sierra. It was worth it to them because they don't want to have to spend $50/month on the software (I actually think the price is like $78/month or something now). It sucked nuts. I had to do a fresh install of El Capitan on a new SSD and upgrade it to High Sierra in order to get it to work.
I also had to do some workarounds to get Dragon Naturally Speaking to work in Mojave. They discontinued the software for Macs several years ago but this guy absolutely had to have it for his job. Paid me $400 to get it working.
Macs make me good money, but God, I freaking hate them. Apple designs their hardware and their software so that everything becomes obsolete almost instantly. They only support their OS for 1-2 years and then they make you upgrade to the new one, which is full of bugs and will only work on basically brand new hardware. 3rd and 4th gen i5/i7 systems are still perfectly usable for a PC and will work for 3-5+ years, but on a Mac it's "obsolete" and can't run the new software. This would be fine if Apple actually supported their old software, but they don't. These 4th gen MacBooks still go for close to $1,000 even though they're basically obsolete thanks to Apple's non-existent OS support. A 4th gen i7 Mac is basically just as obsolete as a Core 2 Duo PC. Worse actually because you can technically still run Windows 10 on a Core 2 Duo PC.