Pressed F8 on my XPS 15 and now I have a boat anchor....

This is unfortunate. A number of posts here mention that pressing F8 when booting the system will brick it. F8 for entering Safe Mode no longer works in Windows 10 although it can be changed to do that. To enter Safe Mode in Windows 10 you should hold the "Shift" key and then click the "Restart" button. Why some Dells are set up to brick on F8 I don't know. Your only choice is to call Dell and see what they can do.

JohnD

Thanks, I'll have to try when they open next week. I had a moment of joy when I remembered that most of my credit cards have a free extra year of warranty but it turned to sadness when I realized that I had used a Dell gift card (which invalidates that extra year).

Well, the only other thing I would try is to remove the drive and boot.  I know it isn't getting into the Bios but on a UEFI system, boot devices are checked before it gets to that point.

What exactly does it do when you try to boot, no F key options at all?    In Win 10 you need to start tapping those keys earlier than you might think.

If you have the external power plugged in, unplug it.

Try holding the power button down for 30 seconds.

Some systems have the ability to recover the bios for emergencies, have you checked into trying that?

No post, no F2/F12, I'd love to do a bios recovery but I don't see anything like that for the 9550. In other threads people have reported pulling the cmos and main battery does nothing to reset it. I've tried the hold down power for a full minute fix. That's not actually for the F8 error, just for display driver issues. They seem to have gotten lumped together due to similar features (black screen) but differ in severity, the display issue recovers after hard power down. I used to have the display issue but realized I could just restart the laptop. Now I wish I had looked into I more in order to know about this much more serious defect.

Thanks for the idea, hadn't seen it in any of the other threads. Unfortunately it's still a brick even with SSD and HDD pulled. Also noted while I had the back off that the fans don't start while it's "on" they only fire up when it press the button again to turn it off. I'm tempted to try and remove the CMOS battery (dell was nice enough to put it on the back of the mobo so you have to remove everything), but I think I will save that bit of futility until I talk to service next week.

Agreed, there's no reasonable reason that pressing F8 should brick a system. I tried using my TV as an external monitor but no boot or desktop screens come across. Also, the fans don't spin up which I'm pretty sure should happen at boot.