Random freezes caused by Windows processes

I installed windows 8 a couple of days ago and from time to time (every 10-15 minutes) my computer freezes completely for a few seconds (can't even move the cursor). The last few times, immediately after the freeze, I hit ctrl+shift+esc to see what freezes the computer and I once saw some Windows Defender process, but more frequently I see the SQL Server Windows NT. They just use my CPU at almost full capacity for a few seconds and then they go back to 0-3%.
I can't explain this and i couldn't find a solution, so i would really appreciate some help.
Thanks.

Please provide this information so we can provide a complete analysis (even though you're not reporting BSOD's): https://www.eightforums.com/bsod-cr...e-screen-death-bsod-posting-instructions.html

At work we run diagnostics on every system that we take in for repair (before we even start working on it). At a minimum, please run the free diagnostics here: Initial Hardware Diagnostics. For more in-depth diagnostics, please run those listed here: Hardware Diagnostics

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