i recently formatted my hard drive and downgraded from vista home premium to xp pro sp2 which i have updated to sp3. i had to search all over the web for drivers that were missing after the xp installation and now after about 3 days of searching i have them all installed and everything seems to be running fine although the fan does not turn on anymore. i have read that this might have something to do with the SM BUS Controller although i have installed the driver and still no fan. my laptop is an acer extensa 5420 with an AMD Athlon 64 X2 Dual-Core processor TK 57, 795 MHz, 3 GB RAM. can anyone please help or at least point me in the right direction. thanks.