I have the same system, only had it about 5 weeks but I was able to install Windows 7 RC x86 with no problem. I did have BSOD issues when I tried to install the x64 version. Right now I am re-downloading x64 and am going to try burning at a slower speed. I have a hdd that I have Vista x64 Ultimate installed on with no issues so my Win7 x64 install was either a bad burn, bad download or the Windows 7 x64 RC is flawed. I will post my results in a while.
When I tried to update my bios, Toshiba said it was already at the latest version.