I had a MSI KT4V Socket A Motherboard with an AMD Athlon XP 2100 with 512 of PC 2700 DDR RAM (2 X 256MB). I have recently upgraded the CPU to an brand spanky new AMD Sempron 2500+ which is Socket A. Phyiscally installing was no problems. Software and Windows XP Pro SP2 problems... Windows does not recognise the AMD Sempron 2500+ instead it says it has a AMD XP 1600 running at 1.4GHz. The FSB is meant to be 333 and so I wwent to the BIOS and changed the FSB from 133 to 166 as required. When I saved it and rebooted the PC would not show anything on screen. pyhiscally things were working, but nothing to show. The monitor actually started to put the standby light on meaning that the PC is not connected, but it was! So I turned it off and took the JBAT pin clip off on put it back to clear to Default changes. several times I tried this procedure and same outcome. I rang MSI and they said to download all the updates for the motherboard and so I did, but no success. The version of the BIOS is 1.7 which is the highest and also I downloaded the update which supports this CPU - Sempron 2500+. The thing is that a modified window poped up saying that this update only supports PCI boards. Work that one out? Is there anyone out there that can help? I was told it could be a RAM issue, but the RAM used to run at 266 for the previous XP 2100 installed. And to change it to 333 (166) should work. 1.4GHz is too slow! I need 1.75GHz! HELP!