Hi, I have an additional 4GB RAM strip, trying to improve to 8GB (4+4). Both of the RAM strips have the same manufacturer and model number and work individually, each in slot 'A'. When I then add the second RAM card to slot 'B', the machine will not start. This indicates to me that slot 'B' is not active or that I need to program slot 'B' to regognize the newly added RAM strip. Can anyone advise on this please? The Travelmate was originally bought with Win7 Pro OS but "free" upgraded to Win10 Pro in 2016 (or 2017). Everything else is as original (Intel i3/chipset, WD 500GB HDD etc.).