Windows 7 stuck in a boot loop at the logo screen

Here is the predicament... yesterday my PC started freezing entirely while I was gaming, so I figured it wasn't a memory issue and ran a MemTest64 diagnostic, which clearly came back clean. I decided to leave the machine off after that. Today, I powered it up only to find myself stuck at the splash screen where the computer just keeps rebooting, offering me the choice between a System Repair or a Normal Startup (though choosing either results in another freeze and immediate reset).

The System Repair tool is completely useless, and I can't even get into Safe Mode because the machine resets itself while trying to load the necessary files. I've run Chkdsk and found nothing, and a System Restore didn't help either. To make matters worse, I can't even boot from a recovery USB; despite having configured the BIOS to prioritize the external drive as the primary boot device, the moment I attempt to boot from it, the system kicks me right back to that repair/normal startup loop.

I am at a total loss as to what else I could possibly try here... does anyone have any ideas on how to proceed?

It could be a failing hard drive, or you might just be looking at a total system collapse if the drive hasn't already given up the ghost. If you can swing it, I’d highly recommend plugging that drive into another PC to run some diagnostics—maybe use something like Hard Disk Sentinel. As soon as you fire up the software, you'll get a clear picture of its actual health status. If you don't have access to another machine, your best bet is to whip up a bootable USB drive using Windows (you can use Rufus to get it done). Try running the installation from there; if the process hangs or crashes right when you hit the formatting stage, then yeah, your drive is likely toast. Even if you actually manage to push the installation through, you still need to run those health tests mentioned above just to be safe.

If you’ve set the CD drive as your primary boot device, the system is supposed to pick it up, period. No excuses. You should probably verify if that disc is actually bootable in the first place.