I don't know exactly for what reasons, but after I did update of the Sun VirtualBox 3.0.2 to the version Sun VirtualBox 3.0.4, the operating system began to fall frequently. Crash. 
Have started to appear erori blue screen whether VirtualBox Roll or not, at that time. It seems that after the installation there have been some changes in drivers, which are not compatible on the system. 
Problem appeared on a laptop Toshiba A300 / Windows 7 RC 7100 / 32-bit
The solution:
REMOVING Sun VirtualBox version 3.0.4 and REINSTALLING / installation of the version Sun VirtualBox 3.0.2.
Download: VirtualBox-3.0.2-49928-Win.exe (version for Windows 32-bit)
We don't know if Bsod is a general problem of VirtualBox 3.0.4 pe Windows 7, but in case there are others who have met this error, we hope this item would be of help.
 
			