After a quick google search it seems that you should be able to run 64bit Windows 7 as long as you have updated to the latest Bios and latest edition of the chip set drivers.
Source: Microsoft Answers
Thanks for the info. I have ASUS Mobo CD (M1284) with AMD 690G Chipset
don't know if the Bios and Drivers are latest ?
My second question is : Should I get Win-XP Pro 64 Bit, or Win-7 Pro 64Bit
and where can I order the OEM. OS. CD. cheapest ? Thanks..