I have a PC that's just over a year old. Today, while playing a game, it suddenly shut down and I smelled a slight smell of something burning(no fire, don't worry!). After this "incident" my pc won't start anymore. First thing I thought of was that the PSU was broken, so I grabbed another one and tried it: no luck, so it wasn't the PSU. After that I started removing non-necessary cards etc: sound card, graphics card, 1 slot of ram(tried all combinations), still no luck. At that point I was pretty sure it was either my CPU or Motherboard.

To be sure I checked everything thoroughly I held the power button for a few seconds with the PSU disconnected(since I always heard this unloads your BIOS battery without having to physically remove it) and tried again: suddenly my PC came back to live. I still had my graphics card, sound card and cpu-fan(had to remove it to access the cpu power connection on my motherboard) disconnected though, and when I tried to connect a screen to the onboard graphics card I couldn't get anything on the screen(even after restart).

After that I reconnected my graphics card, and the PC wouldn't start again(it'd flash motherboard lights for less than a second and move the fans slightly(also those of the graphics card) but nothing more). Now I'd think it's my graphics card that's broken. But can that even prevent my entire PC from starting? And then why didn't my pc start the first time I removed it?

Can anyone of you reason out what's wrong with my PC? Or give me directions I could still troubleshoot in? I don't have another PC I can test the separate parts in.

Hardware list:

• CPU: Intel Core i7 4770K / 3.5 GHz
• PSU: Corsair CX Series Modular CX600M
• RAM: Corsair Vengeance 16GB
• CPU-fan: Cooler Master Hyper 412S60
• GFX-card: MSI N780 TF 3GD5/OC (GTX 780)
• Motherboard: MSI Z87-G45 Gaming

I have a PC that’s just over a year old. Today, while playing a game, it suddenly shut down and I smelled a slight smell of something burning; no fire, don't worry~ After this “incident” my PC won’t start anymore. 

First thing I thought of was that the PSU was broken, so I grabbed another one and tried it: no luck, so it wasn't the PSU. After that I started removing non-necessary cards etc: sound card, graphics card, 1 slot of ram(tried all combinations), still no luck. At that point I was pretty sure it was either my CPU or Motherboard.

To be sure I checked everything thoroughly I held the power button for a few seconds with the PSU disconnected—since I always heard this unloads your BIOS battery without having to physically remove it—and tried again: Suddenly my PC came back to life. 

I still had my graphics card, sound card and cpu-fan—had to remove it to access the CPU power connection on my motherboard—disconnected though, and when I tried to connect a screen to the onboard graphics card I couldn’t get anything on the screen even after restart.

After that I reconnected my graphics card, and the PC wouldn’t start again. It would flash motherboard lights for less than a second and move the fans slightly—also those of the graphics card—but nothing more. Now I’d think it’s my graphics card that’s broken. But can that even prevent my entire PC from starting? And then why didn’t my PC start the first time I removed it?

What’s wrong with my PC? What could I still troubleshoot in? I don’t have another PC I can test the separate parts in.

Hardware list:

• CPU: Intel Core i7 4770K / 3.5 GHz
• PSU: Corsair CX Series Modular CX600M
• RAM: Corsair Vengeance 16GB
• CPU-fan: Cooler Master Hyper 412S60
• GFX-card: MSI N780 TF 3GD5/OC (GTX 780)
• Motherboard: MSI Z87-G45 Gaming