If you are seeing a message like this:
Invalid BOOT.INI file
Booting from C:\windows\
That usually means the c:\boot.ini file is missing, but you can replace it.
For the file to be missing would require some extra effort since it is normally a hidden, read-only, system file, but I can think of many things that are happy to delete it for you.
If the system used to work properly, what do you think happened to the system since the last time it did work properly?
Do you now or have you ever had the Ask Toolbar installed on your system?
Have you now or nave you ever used any third party applications on your system where the product description includes such descriptive phrases as:
cleaner, mechanic, detective, doctor, cure, optimize, clean up, tune up, speed up, fix up, compact, compress, faster, power, boost, booster, eraser, muncher. guaranteed or anything that has an icon resembling a wrench, spanner or screwdriver?
In a single partition installation XP does not even need a c:\boot.ini file to boot – it will complain, but it sill still boot.
You need to create a new c:\boot.ini file. It is just a text file so you can use any text editor such as Notepad or WordPad to create a new file.
Here is an example of a simple c:\boot.ini file you can copy/paste the text to make a new file.:
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=”Microsoft Windows XP Professional” /noexecute=optin /fastdetect
When you get that text entered into your text editor, do a Save As… and save the file as:
Respond in the affirmative if asked to overwrite or replace the existing file.
Then reboot your system.
If the file comes up missing again, we will have to figure out why and fix it.