You are kinda in a world of hurt right now. The easiest thing might be to clone you C: to a larger SSD. Many SSDs come with cloning sw or free ones avail. on the web. Get a 512GB or 1TB ssd if you can so you have some spare space afterwards.
You might remove some files from the C: now to give a bit of space for the OS. It doesn’t work well at all with so little available space.
Your d: drive appears to be either SSD or NVMe (or maybe a small HD?). You have plenty of space to move your dbs there. Currently, those dbs are totaling somewhere around 60GB, so if you move them, you will have some headroom on your c: drive. Although, as @Fuzeguy suggested, depending how you use that box, you may want to start looking for a bigger SSD.
Stop chia, make sure that it is not running (reboot if in doubt)
To move your dbs,
create ‘chia’ or something like that folder on your root d:
in that folder two additional folders:
2.1. ‘blockchain’ and
2.3. ‘wallet’
Once you have those,
move the content of %userprofile%/.chia/mainnet/db/ to d:/chia/blockchain and
move the content of %userprofile%/.chia/mainnet/wallet/db/ do d:/chia/wallet
Make the following changes to your %userprofile%/.chia/mainnet/config/config.yaml
Once you have it done, open two explorers for those two folders (d:/chia/…), and start chia. You should see new files created in those folders (*shm and *wal - should have 6 files in each folder). If those files are not there, you have missed something, and chia either doesn’t know what to do (e.g., added some extra space / char to config.yaml), or is still using dbs on c: drive.
Currently those dbs take ~60GB, so you don’t need yet 512GB drive to hold them. Chia is working on compacting those dbs, so no need to rush to get 512GB if you have another 128GB or 256GB handy.
It is recommended to use NVMe or SSD, but it also depends on what CPU you have. If your CPU is really strong (a single core performance), you may still be able to run it off a HD, but the keyword is “may.” In case mem pool will get elevated, that HD may be a bit too slow. However, there is plenty of RPi owners that run those dbs on HDs.
So, whatever that d: drive is, for now is good enough. Once you make that transition, you can check how it will work, and whether you need to get another internal drive.
When you plot using MM, what are your settings? Are you using that d: drive for plotting? That would basically kill d: drive db performance. If you are plotting on that d: drive then either you can plot or farm, but not both.
UPDATE
Actually, wallet db is around 10GB, and doesn’t require too much performance. So, you could move just wallet db to your d: drive. That will give you some headroom on c: drive for blockchain db, and your plotting would not interfere with your farming (yes, your wallet may be staying behind, but should be catching up, but potentially that is not a problem for farming). Although, this is just a short term solution.
Also, you can delete everything from your c:\windows\temp folder just to get some breathing room.
Not sure what is causing your posts to be marked as flagged (as inappropriate). Maybe that is done automatically due to those links to images. Just copy your images directly, don’t use external links, as no one wants to click on unchecked links.
There is no need to move “the whole” chia to d: drive. There are basically just two big db files, the rest is rather nothing.
I also don’t know how to let base chia know that you moved chia to d: drive. I guess, you can search that folder structure for “.chia” and maybe something will show up. However, that may not work well, as once you upgrade, that folder is killed, and a new one is made. Although, you can use a junction to point to that d: drive. You can search this forum how to use junction.