Successful Windows 11 install (and triple-boot) on ThinkPad T400: It was a pain in the ass but I managed to get Windows 11 running smoothly on a ThinkPad T400 from 2008 with
Lenovo ThinkPad T400 T500 500GB Hard Drive, Caddy, 10 Pro & Drivers Preinstalled | eBay
Lenovo ThinkPad T400 2768 | www.shi.com
Lenovo ThinkPad T400/T500/R400/R500 Recovery Discs (Windows Vista Business/Ultimate x86 SP1 - English) - 46V3016 : Lenovo : Free Download, Borrow, and Streaming : Internet Archive
Lenovo T400 -39T7454 keyboard for laptop AAH4 (IA1)
I-have-a-question-about-a-T400-slot - English Community - LENOVO COMMUNITY
Windows XP / 10 Dual Boot Lenovo ThinkPad T400 2.26 GHz 4GB 120GB SSD Bluetooth | eBay
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Screen Brightness on Lenovo T400 – irrationale
Lenovo ThinkPad T400 T500 500GB Hard Drive, Caddy, 10 Pro & Drivers Preinstalled | eBay