Today I called Microsoft to activate WinXP, answered questions and followed instructions after which it indicated activation was successful and that I could resume using WinXP. However, the system won't even post after restart. Now when power on the system the monitor displays in the lower right corner A1 then A2 and finally A3 where it stays with no post and blank screen except for the A3 in the corner. It's WinXP Pro SP3, and motherboard is MSI Z77A-G41 motherboard with Pentium G2020 LGA 1155 CPU and 2GB Mushkin DDR3 1333 RAM if any of that is important. Can Microsoft activation kill a system, or did the new motherboard installed just yesterday die already? Does anybody have any explanation or possible fix for this odd problem? Is there a Microsoft contact I can try to fix the problem since it happened immediately following the activation?