In the last 2 months I installed a graphics card given to me (Geforce GT 740 SC- this is just so ya'll will know what I did before these problems started happening) the first 2 weeks was alright, nothing happened. Then my PC would randomly restart, usually within 5 minutes of turning it on. This wasn't happening TOO frequently, maybe once every 3 days. I kindof brushed it off. (that is still happening btw). Then starting about 2 weeks ago, I was playing World of Warcraft, then all of the sudden the game freezes and I get a quick Blue Screen telling me of the "Video Scheduler Internal Error". I disregarded it at first, until it happened again. I looked up the message and concluded it probably had something to do with the OC I put on the GPU. So I lowered it a bit, and that hasn't happened since. Then today is what scared me the most. (Keep in mind i recently bought a new HDD because the old one was toast) I start up the PC, open up Youtube and watch a video for maybe a minute and the screen freezes, I hear a really fast "popping" noise in my headset and the PC restarts. I open Youtube again and start watching another video. 2 minutes in it does the exact same thing then restarts. After that Windows 10 is booting up and I get the "Windows 10 did not start properly" screen and just pressed continue to Windows 10. Since then (about 30 minutes) nothing strange has happened. I am still very scared though something might be wrong with this PC.