[critikal17]

I'm a little worried about my HDD and PSU. They're both quite old.

In terms of the HDD, upgrade to an SSD.

Believe me, you will notice a significant difference with read/write operations, and shutdown & boot times. Around 18 months ago, I spent over 15k upgrading my systems and the gain In performance Is second to none.

Yeah that's what I was thinking. I don't plan on spending more than $200 in total. SSDs are somewhat cheaper than they used to be, and I never needed that much storage to begin with.

If you're going for an SSD, I'd take a look at M.2 ones if you have the slot on your MB.
These two are great picks, both on sale on newegg right now and the price is hard to beat. 1tb of SSD storage is a lot and the read/write speeds of M.2 are unmatched.
Intel
Sabrent

They're both a little over a hundred, which leaves enough in the $200 budget for a PSU upgrade as well, and believe me, you want that, I lost a motherboard and 32 gigs of ram to a shitty power supply.