GRUB failure after updates

[mat715@comcast.net]

I have a single core pentium processor system. Not sure about the version of Debian Linux however I do know:

GRUB v1.99-27

 

GNOME Version 3.4.2

 

32 bit O/S

For several years  I have used this hardware with Windows XP and Debian in a dual bootable system through GRUB. Yesterday I loaded Debian and received a number of updates over the Internet. On the next reboot I lost  the ability to boot to the XP O/S.

How do I get the choice of both XP and Debian as operating systems back?

Thank you,

Mike Tremblay