I’d start by going into the BIOS and verifying the time is correct, then go back into the BIOS and do a system diagnosis. Check the RAM, but it usually passes. Then check the hard drive. Let the test complete. If it passes you will need to reset or reinstall your operating system. If the hard drive is bad, remove it and gently shake it to check for any sounds. your hard drive should remain silent, a noisy hard drive should get replaced. Best place for parts is ebay-never by any hard drive used, always new. If you don’t have your operating system disk, Microsoft offers them free if you are willing to enter your product key. Linus operating Systems are free to download from distrowatch.com. I use nothing but Linux Operating systems, they are easy to install, they replace Windows or allow a dual boot. Remember to add the dvd drivers, flash. I use Whale Browser. Personally, I’d check the fan and replace the thermal compound on your CPU. Never took a computer apart before? Go to youtube and type in your device...