[maxtoralias]

To locate boot.ini file, go to control panel, select SYSTEM, ADVANCED, START UP AND RECOVERY Settings and then click on EDIT and change to the following or similar.
This is a typical bott.ini file that you would need to modify yours to. If using windows xp home edition, just substitute HOME for PROFESSIONAL

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOW S
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micro soft Windows XP Professional" /fastdetect /NoExecute=OptIn

Once changes made, click on save (this will be in NOTEPAD format)
You may also need to ensure that the modified boot.ini file is shown as the default operating system

Hope this helps