Of course a good new PC can always be a big help. Probably outside of your intentions, but I do want to mention that I switched from a desktop to a laptop a couple years ago and it was a huge help to my music output. The power of good laptops these days fully keeps up with music production needs. Laptops are not necessarily that expensive.
Two keys for my laptop that have made things fantastic: two internal hard drives, and both of those hard drives being SSD.
For me, the laptop approach is great because I can work in my studio area when I'm feeling creative and need all my outboard gear, or I can bring the laptop into another room and I can still use it for Sonar editing, and I can keep doing stuff with it.
I've even kept the creative flow going when traveling. I suppose you could do that with all of that tablet based software now, but I like the full PC feel of Sonar and all of the tools at my disposal on my hard drives. Bottom line, I'm able to get in more time with music production as a result of having the Sonar environment move around with me rather than being stuck in one room.