Hello reedsfiremom,
Insert Vista installation DVD into your computer drive.
1. restart your computer.
2.Press a key when it prompted PRESS ANY KEY TO START FROM CD-ROM.
3.Select a language and click Next.
4.Click Repair your computer.
5.Click the operating system that you want to repair, and then click Next.
6.In the System Recovery Options dialog box, click Command Prompt.
7.type bootsec /fixboot or bootrec /fixboot.
then your computer bootmgr will fix
.