Do a google search for "t7500 reboot bios" or so, and you will find a few threads about this issue.
The issue is that BIOS version A12 and A16 made reboot problems for the computer. The computer is trying to reboot for like 20 times (about 10 minutes) until it successfully rebooted to windows. Yes, this happens every single bingle time you try to reboot.
The only solution was to downgrade the BIOS to the A09 version, which I did so. And that is the solution you will find on the web for this problem.
Sadly, Dell never budged to try to fix it in A12 or A16.
Now, just a few days ago, Dell released a new version A17 for the BIOS.
My excitement faded away right after upgrading my BIOS to this new version, because right away my computer started having the same reboot problem.
So, hey Dell, please fix the reboot issue once and for all, so we can have sensible reboot experience and protection of the CVE-2017-5715 vulnerability simultaneously.
Thanks for your quick action on this (hopefully).
Same issue here, I have updated the bios to the latest A17, the system work fine after the first reboot. After that it has gone back to doing the same. Any ideas or workarounds?
If Legacy-BIOS based, you should be able to flash firmware from DOS (outside Windows).
If UEFI-based, there should be an option to flash the firmware from initial UEFI environment (usually F12 on boot of a Dell).
Just for the curiosity to see if I can solve it after others and Dell gave up on it, I'd be ready to designate an half an hour to try helping you updating the BIOS, if you would want to give me TeamViewer access.
Of course don't share here in public any credentials, just let me know here if you are interested, and we'll take it from there.
Thank you for your kind help. I've even tried installing the ROM files using command prompt but nothing and quite unsure really what I'm doing.
I will get in touch to allow you access when it suits you. Thanks again Paul