What Happened To My Indexing Options?

A few days ago, I used to be able to see my two other drives in the left box. Where did they go?

I press the "Modify" button, and I get that Window on the right. What's that dp://{###....) folder?
Why are there certain folders that are excluded from indexing? I want them to be indexed, yet there is no option to fix that.

Now searching for files in the other hard drives takes forever and is very inconvenient.

You are going to have to look at the C:/ drive to see what that folder does. You will have to allow hidden System folders to show.

Indexing is by default to only search certain user folders, along with Program folders. Personally I do not like using it, because if it resumes while you are using the computer, it slows everything down.

All hidden files/system files are set to be visible for me to see. I can not find that dp:// folder anywhere.

I've never had issues with indexing; it makes things a lot more smoother and easier to find files since they are all indexed in one location of all the files' names on the computer; no need to search everywhere. Never slowed the computer down. What about my other hard drives, why do they not want to show up anymore?

You probably need to re-index the files, to update the database. If you click on that directory, it will show you in the folder list, where it is located.

I rebuilt the database files, thanks. Now there are ~200,000 files indexed instead of the ~400,000 files in that image above. So many files, why?

I clicked that dp:// Directory and it said some option that I wasn't able to find..? I dunno what that's all about.
So instead, I unchecked that folder's box (to see what happens) and pressed OK. I went back to that Indexed Locations box to see what happened, and it apparently disappeared; it is no longer there. Okay...? One down, and now the other issue:

I still do not see my two other hard drives. How do I get them in here?

If you go into Modify it should see the other hard drives if they are permanently installed. You could try Speccy to see if it shows all hard drives. This is for 7, but should work with 8. Change advanced indexing options

They are permanently installed, that is right. But if you look at the picture above on the right, that window is what the Modify button shows up. I just tried it right now as well, and I only see the Main Hard Drive (C:\). Why are they not showing up?

So what's wrong with this option, can anyone tell me why this is happening?
Also, when I search in a folder on one of the external hard drives, it takes MINUTES until it starts finding results...
In a folder of about 6,000 files, no sub-folders, it takes minutes until results are shown.

When I first installed Windows 8.1, it took just a few seconds to find all the results, even without the indexing options set up.

What's going on?