This sounds like the Toshiba value added package may have replaced some of the core DLLs without properly registering the changes. Even re-installing Windows may not cure the problem if you re-installed over the previous installation.
Did you try installing to another partition, or re-formatting your hard disk before installing again? I know that's a lot of work for a newly installed OS, but sometimes OEMs (like Toshiba) take a few liberties with their software in order to make their products appear faster, even if it has a negative impact on overall system performance.
Another possibility is that you have a virus/trojan, a root kit, or even a spam-bot that got into your system. Try using one or more of the AV boot CDs to scan your system. If you have been root kitted, it may be the only way to detect it.