CPU is not detected on my ENVY 360 convertible laptop

[sranangmang]

Screen is black, I get 3.5 blinking LED codes saying CPU is not connected.  

[WAWood]

@sranangmang 

The actual error page says that can be CPU failure OR system board failure -- and both of those are serious and very expensive to repair because the CPU can not be replaced on its own, and a system board replacement, even if available, which they usually are not, can easily cost you more than replacing the PC.

If your PC is still under the original one-year HP warranty, or if you have purchased an extended warranty from HP and this is still valid, then having HP do this is an inexpensive option for you. In that case, you should contact HP Customer Support to see about having it repaired or replaced under warranty.

To contact HP Support see the following link to create yourself a case number:
Step 1. Here is the link: https://support.hp.com/us-en/contact-hp
Step 2. Enter Product number or select to auto detect
Step 3. Scroll down to "Still need help? Complete the form to select your contact options"

Case number and contact information appears.
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If your PC is no longer under warranty, then it will cost you up front to have HP examine your PC. If you want to do that, you will have to contact an HP Repair or Service Center to see if they can examine the PC to determine the cause(s) of the problems, if it can be repaired, and an estimate of the repair costs.

Since you live in the U.S., here is a link to the HP Service Repair Centers:
https://www.service-center-locator.com/hp-hewlett-packard/hp-hewlett-packard-service-center.htm

If that link does not get you a useful page, then use the main HP link:
http://www8.hp.com/us/en/contact-hp/ww-contact-us.html

Good Luck