I've recently attempted to upgrade my old Dell Precision M4800 from Windows 7 to Windows 10, but I believe I screwed something up in the process, because it doesn't seem to boot properly anymore.
I removed the Windows 7 drive and installed a blank 1TB SSD into the slot, then plugged in a Windows 10 installer USB drive. While it loaded the drive I noticed some strange blue-ish lines randomly covering parts of the bottom half of the screen, but when the Windows USB loaded, they were gone. I installed Windows 10 but forgot to change the BIOS boot settings from Legacy to UEFI, and believe that's what caused an "Invalid Partition Table" error message when it restarted.
I was able to boot to the BIOS and change it to UEFI, and Windows loaded properly, and I was able to get halfway through the setup process when the mouse and keyboard froze...they just became unresponsive. Plugging in an external mouse did not help, it didn't look like the mouse was getting any power anyways. So I powered off the computer and turned it back on, and it gave me a blue screen, and I just powered it off again and booted back to the USB (also there were some white-ish lines on the bottom of the screen) and went through the Windows setup process again.
This time, after it rebooted, I got through the setup process, but it froze again, and after powering off and rebooting it, I got a blue screen again, and the computer restarted into recovery mode and went into startup repair, then booted successfully to the login screen. After logging in it gave a notification that it uninstalled some updates to fix the problem, which I suspect had something to do with the display...maybe it had installed some bad drivers in the background while I went through the setup process?
Anyways, it still was installing some updates in the background and restarted, I believe, when I was not watching it, but when it was complete, the battery must have died and when plugged it in and tried to boot, nothing would happen...just some fan noise and a blank screen. I removed the drive but that didn't change anything, and I still couldn't access the BIOS at all or even see the Dell logo when booting up.
I tried removing the CMOS battery for a solid 30 minutes but my situation remained the same, and now I'm not sure what to do. I've been able to access the BIOS occasionally...though I don't know what I'm doing to get there...once when I pressed F2 repeatedly it showed the Dell logo after about 30 seconds, and I was able to access the BIOS and reset the settings to the defaults, but nothing changed, still a blank screen. Also I successfully ran the display diagnostics by holding D + Power Button, but that did not change anything either. I was also able to run some system diagnostics by holding Fn + Power Button, and they ran without errors also...but this computer only seems to let me into the BIOS randomly, and I'm at a loss here.
If anyone has any suggestions, please let me know. I'm not much of a hardware guy so I'd appreciate any insight on what I can do to get this working, if possible. Thanks.
