I once had a similar problem and was instructed to do the following, but be carefull. If you are unsure about this then wait for entwisi to reply ( recommended).
Click Start, click Run.
Enter msconfig and click OK.
Click tab Win.ini to bring it to the front.
Click the [+] sign beside [windows] to expand this item.
If you see an entry run= involving \vtagent\reboot.exe, then uncheck it.
Click OK to exit the System Configuration Utility.
