Computer turned on, but monitor says no signal

[bigrigjaden]

I just built a new pc, so now I have my old one sitting around. Its only been a couple days since I have turned it on. I removed the hard drive from my old computer and put it in my new computer. I put in another hard drive that I had laying around in my old computer. But when I turn the computer on, I get no signal from the monitor. What could be the issue? On my old computer, I did have to take out my heatsink to take out the hard drive, but I put it back. Also, with the random hard drive I put into my old computer, I don't think it had an OS installed. I tried plugging it into my new computer along with my SSD with an OS and my other hard drive, and it was recognized just fine as another hard drive. But when I tried using it alone in my new computer, it would say that windows failed to start, or something along those lines and gave me the options to start windows normally or in safe mode. I tried safe mode, but then my computer rebooted and brought me to the same screen. Which is the problem? Would I be able to have just the broken hard drive plugged in and reinstall Windows 7?

Sorry if my explaining was a little confusing. I kinda just typed and tried to explain it quickly. Please ask questions if needed. Thank you

 

[Xivilain]

Check all the cables you might have touched. Are they all plugged in and seated properly? Power supply to motherboard? Etc?
Did you reapply thermal paste on the CPU after removing the heatsink?


Without an OS on the HDD, the old computer should POST but not BOOT up anything. So you should see a message on the screen that says "Insert Boot Media and Reboot". If it does have Windows 7 on it, then it should boot fine. Check the old PC's BIOS settings for Boot order, and make sure the HDD is at the top of the list to boot first.

Windows can say it "failed to start" because you may have shut down the PC without properly letting Window shut down first. Its a standard message. You don't *need* to use Safe mode here, because you were simply moving the HDD around different PCs.

Check out this nifty guide on "system won't boot" / "no video output" issues:
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems

Let us know what you tried, and if its working again.