If you have any non-essential devices attached to your computer, disconnect them.

It is possible your install media is corrupt.

Did Windows 7 come preinstalled on your PC? If so does it have a Recovery?

The only thing plugged in was the mouse, and keyboard.

Yes, I took my pc into a shop to get fixed because it had a permanent blue screen. And he told me it was Windows 7, I gave him the benefit of the doubt because I knew what it was, i just couldn't fix it.

When I got my computer back a day or 2 later it was on Windows 10.

How would I find out if I have recovery?

Sh*t shop it sounds like LoL, that would never fly where I work. You most likely don't have a recovery partition anymore because they probably wiped that with the fresh install.

Back up any data you want to external HDD or thumb stick. You could put it on a new partition, but make sure you don't delete it when you are reinstalling.

Redownload Windows 7 through this.(You are going to need your product key located on the case)
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I would recommend Power ISO to burn it (nothing special about it, I just personally like it)

I pretty sure to select boot device for HP is esc or f12 on start up. Select CD/DVD drive and then select custom install, not upgrade. Delete the partitions that are there and click next and then you should be all set.