I recently made the dumb mistake of updating my bios from like bios 5 to 12 since i'm getting a new graphics card soon and heard that you have to update the bios first. As expected, it went wrong, and it crashed during the reboot and all day have been stuck at a black screen when starting my PC saying to choose boot priority or something.

Finally, as I was trying everything to do in the F12 menu, I decided to switch the boot mode to UEFI from Legacy. It actually booted after doing that, and luckily my hard drive is intact, but there were some interesting things I noticed. First of all, the space of my HDD seemed to decrease slightly as I realized when going to my PC. Second, there was some weird stuff with Alien Autopsy (not really sure what, but it brought up an error message). Also it might be running a tiny bit slower. Hard to tell. It boots slower as well.So, is changing the boot settings dangerous, or did I do the right thing? Or did I just ruin my PC today?

I have an Alienware Aurora R4 running on Windows 7.