January 8 2019 I started this thread and now I will end it. I installed WIN7 64-bit Professional. I just went to eBay and purchased for $64: "Crucial 2x4GB PC2-8400 DD2-800Mhz DDR2 200pin SODIMM Nonparity Laptop Memory RAM" https://www.ebay.com/itm/Crucial-8GB-2x4GB-PC2-6400-DDR2-800-200pi...

Dear Volker Stoeffler: I can only share my own experience. I have a T731 and a T4220 - that shared the same Full Disk Encryption [FDE] password. They are very similar machines.The T4220 FDE drive failed and I replaced it with the T731 FDE drive. I was astonished -it worked. Wow! I have no idea if yo...

The Fujitsu Lifebook T4220 (configuration # A1A5J3E615B50010; Serial # R8600632) was not manufactured in contemplation of WIN 7 64-bit.

Here is my question: will the Fujitsu Lifebook T4220, under WIN7 64-bit, address 8 GB RAM?

Fujitsu Secure Disk Protocol : aka Full-Disk Encryption [ FDE ]; Self-Encrypting Drives [ SED ]; Trusted Machine Protocol et al. https://en.wikipedia.org/wiki/Trusted_Computing I have learned that a Fujitsu T4220 SED , which will not even boot until the key is entered, can be booted when installed ...