Hi, I recently updated my computer with a new graphic card and power supply of 500 watts. I downloaded a couple of games online, but could only play for 5 minutes and my computer restarted itself. Oh yeah, I forgot to mention while playing the game. I smell something burnt. I think it's coming from the power supply. I have no clue what to do from here and don't know what is causing this, but I do know for sure it's not the game. People been telling me to buy a new graphic card or power supply. However, I need to know what is causing this. Can you tell me what I should do? I'm willing to buy a new power supply but not a new graphic card. Please help?

Well can you supply a bit more specs?
Graphic card model?
Processor with clocking speed and whether it's over clocked or not?
Motherboard model?
Cause by how you describes it, sounds like your new graphic card isn't getting enough power so when you stress it with a game the entire computer doesn't get enough power. I suggest buying a 700 watt power supply for gaming as games can stress computers. Also make sure to clean your computer from and possible dust. When cleaning the fans (if using an air pump) stick something so the fans don't spin and accidentally burn out the motor. If you're over clicking and smell something I suggest you go back to your normal clock speed as it could be your CPU heating up past what your fan supports.

Are you certain it's a burning smell and not just the smell of new electronics? Some smells are normal with new electronics.

As mentioned we need to know more about the rest of the hardware in your computer. Give us makes and models. Also, which video card did you get? Most video cards also require that you plug a power cord into it from the power supply.

And if you already purchased them new, I wouldn't spend the money again for replacements if one or both are defective. You should either return them to the retailer or the manufacturer.

Finally, make sure that all fans spin when your computer starts up. Make sure that you are running the latest drivers for your new video card and that you completely remove the previous drivers. If you have embedded graphics on your motherboard, disable it through the bios.

If you smell something burnt, I suggest you to check your power supply inside fan. If the fan is working then I suggest you to check visually the fan of your CPU even it is spinning, sometimes it loss the fan and when you try to load huge program it will automatically restarting. I experienced that before and I hope this post can help you.