BSOD after changing system locale then "Insert proper boot device"

Trying to play a game and since it's Jap, I had to change the system locale to Japan.
After rebooting, because it requires a reboot, I got a BSOD in about a minute. I thought it was okay and wouldn't happen again because it ran out of memory or something. After I reboot, I got another BSOD and now it's saying "Reboot or insert proper boot device.

I went to the BIOS and my HD was the first boot priority. I'm a total noobie when it comes to computers.

I have an ASUS K52F-BBR5 Notebook.
Could my HD be corrupted or is there a way to fix this?
I'm currently finding my installation disk to see if I can do a startup repair.
Sorry for the lack of info.

No USBs are connected, No CDs either.
Disabled CD/DVD and USB, same thing.
Same results

Hmm, couldn't find my original installation disk so I used an iso.
It didn't detect the disk.

I booted from the DVD and there was a pause before it said Insert proper boot device.

I'll see if I can get the installation dvd working.

Ah whoops. Didn't burn correctly.
Oh no, it doesn't list my OS. D:

Okay, I did startup repair and it worked. I wanted to see what caused the BSOD and apparently it's the game.
The error is DRIVER_IRQL_NOT_LESS_OR_EQUAL
Would you mind assisting me with that, if you know why I get that error?

It's okay if you're busy, I don't mind

Startup Repair diagnosis and repair log
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Number of repair attempts: 1

Session details
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System Disk = \Device\Harddisk0
Windows directory = D:\Windows
AutoChk Run = 0
Number of root causes = 1

Test Performed:
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Name: Check for updates
Result: Completed successfully. Error code = 0x0
Time taken = 0 ms

Test Performed:
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Name: System disk test
Result: Completed successfully. Error code = 0x0
Time taken = 0 ms

Test Performed:
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Name: Disk failure diagnosis
Result: Completed successfully. Error code = 0x0
Time taken = 172 ms

Test Performed:
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Name: Disk metadata test
Result: Completed successfully. Error code = 0x0
Time taken = 47 ms

Test Performed:
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Name: Target OS test
Result: Completed successfully. Error code = 0x0
Time taken = 280 ms

Test Performed:
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Name: Volume content check
Result: Completed successfully. Error code = 0x0
Time taken = 468 ms

Test Performed:
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Name: Boot manager diagnosis
Result: Completed successfully. Error code = 0x0
Time taken = 921 ms

Root cause found:
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Boot manager is corrupt.

Repair action: File repair
Result: Completed successfully. Error code = 0x0
Time taken = 0 ms

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