Problems with bootable partition not being available at startup

I'll do my best not to be a "help vampire" here, but it looks like I've painted myself into a corner, as Wendell would say. I've spent a long time pulling my hair out trying to figure out how to solve this problem, but I think I need to ask for help.

Originally, I was trying to dual boot Windows 10 and Arch Linux on my SSD. I set up a partition to fit Linux on, wrote Arch to it, set Arch up, and ran into some problems. I wasn't getting any video output (Yeah, even with the "nomodeset nouveau.modeset=0" solution I kept finding online) and I needed to get back to Windows. I realized that Arch was the only option on startup, despite me making separate partitions for Windows and Arch. To my relief, the partition for Windows was still there when I ran GPARTED (an ISO/mini operating system one runs to view and manage partitions without the need for an OS, hope that makes sense), although flagging the Windows partition as bootable again still made Arch the only option on startup.

So my question is: is there anything I can do here? I have my data on Windows backed up, but not the actual copy. I would have to buy it again if the partition is unusable.

Haha I realize Arch was not a good idea for a guy kind of new to this like me. If I can figure this out and get back to just the Windows partition I'll probably dual boot it with Ubuntu, which is something I'm very familiar with doing.

Thank you so much in advance, I'm trying not to be a "help vampire" but I couldn't find any solution to the corner I've painted myself into!

Install windows, then linux. Past that you can go back to the arch bootable disk, follow through the bootloader steps to reinstall grub, and be good after that.

I have nothing to install Window from. Is there anything else I can do to boot the partition again?

I'm not a dual boot guy or an Arch guy but from what I know of it you will have issues like this when you have a UEFI windows install, AFAIK theres some special sauce you have to use with grub to make it work in this use case. Do you know for a fact how you were booting windows previously?

For future purposes, its way easier IMO to use separate drives entirely, disconnecting the windows drive to install linux on one, then using the motherboards boot options to pick which you want.

I'm not sure. Is there anything I can do to find that out? I'm using a Z97 motherboard from ASRock, if that helps with anything.

Well, partition information is a quick go to, as well as bios settings. If the drive is in GPT then its UEFI, if the bios is set to boot that drive as UEFI then thats how windows was likely running.

Also, this might yield some useful information.

Looks like if you were using UEFI, rEFInd should get you back on track.

The partition for Arch was LBS according to GParted, and the partition for Windows didn't have any flags.

Rejnstall grub. I just meant the next time you do it.

Check your bios settings then.

I know which partition contains Windows, is there a way I could direct GRUB to that partition rather than reinstalling it?

Working on rEFInd; should I use the USB image since neither Windows nor Arch is accessible?

Edit: it's working on the flash drive, but it still only recognizes Arch.

Its a good possibility then youre not using UEFI. You really should become a little more versed in this kind of stuff before delving into linux but ill try not to make you feel bad since this is a learning experience I had as well. If you dont know how your setup works, its kind of hard for me to help you.

For now, because I know nothing about your setup and you dont seem to know either, we need to get windows working again.

Get a copy of the windows 10 ISO. You can torrent it, you can get it from microsoft, doesnt matter how, but you need it.

Then youll need to boot it via your favorite method (probably USB) and choose its repair option. See the end of the link I posted earlier. If you dont know how to make a bootable windows USB, rufus is a decent utility for windows.

You might be able to get away with using the startup repair in the windows repair utility, otherwise youll have to use the above.

Okay, I'm working on the Windows bootable right now.

You're absolutely right with me being underqualified to be trying to do Arch stuff. I read a lot about this stuff being difficult, but I had thought that I'd be okay since I've used the Ubuntu dual boot tool (feels like the Fisher Price version of this in hindsight) and way underestimated what I was getting into. Good lesson, though. Thanks for helping me out with this.