Press F8 repeatedly after restart to get advanced menu options, can you enter safe mode?
If you can, check your boot.ini file located in C:
click on My Computer, then local disk C: and your boot.ini file should show right there after all other files.
this is what it should look like for just one OS, (this is mine and I use xp pro)
[boot loader]
timeout=15
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect
I also use the recovery console and safe mode in my boot.ini.
you can edit your boot.ini by right clicking, choose open, and edit if it does not say like above.
You should install the recovery console and you do not need your installation cd to do that just a working computer and a cd drive, follow the instructions here:
Here's how to make a bootable xp recovery console cd
If you have no bootable XP media (or are not sure what you have) create a bootable XP Recovery Console CD and be sure what you have (no XP media required).
This is not the same as any recovery disks that might have come with a store bought system.
You can make a bootable Recovery Console CD by downloading an ISO file and burning it to a CD.
The bootable ISO image file you need to download is called:
xp_rec_con.iso
Download the ISO file from here:
http://www.mediafire.com/?ueyyzfymmig
Use a new CD and this free and easy program to burn your ISO file and create your bootable CD (do not install UniBlue or the Ask Toolbar - ever!):
http://www.imgburn.com/
Here are some instructions for ImgBurn:
http://forum.imgburn.com/index.php?showtopic=61
It would be a good idea to test your bootable CD on a computer that is working.
You may need to adjust the computer BIOS settings to use the CD ROM drive as the first boot device instead of the hard disk. These adjustments are made before Windows tries to load. If you miss it, you will have to reboot the system again.
When you boot on the CD, follow the prompts:
Press any key to boot from CD...
The Windows Setup... will proceed.
Press 'R' to enter the Recovery Console.
Select the installation you want to access (usually 1: C:\WINDOWS)
You may be asked to enter the Administrator password (usually empty).
You should be in the C:\WINDOWS folder. This is the same as the
C:\WINDOWS folder you see in explorer.
The Recovery Console allows basic file commands like: copy, rename, replace, delete, cd, chkdsk, fixboot, fixmbr, etc.
For a list of Recovery Console commands, enter help at the prompt or read about the XP Recovery Console here:
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/recovery_console_cmds.mspx?mfr=true
A good idea before starting things is to first verify the integrity of your file system using the chkdsk command.
From the command prompt window run the chkdsk command on the drive where Windows is installed to try to repair any problems on the afflicted drive.
Running chkdsk is fine even if it doesn't find any problems. It will not hurt anything to run it.
Assuming your boot drive is C, run the following command:
chkdsk C: /r
Let chkdsk finish and correct any problems it might find.
It may take a long time for chkdsk to complete or it may appear to be 'stuck'. Be patient. If the HDD light is still flashing, chkdsk is doing something. Keep an eye on the percentage amount to be sure it is still making progress. It may even appear
to go backwards sometimes.
You should run chkdsk /r again until it finds no errors to correct.
Remove the CD and type 'exit' to leave the RC and restart the computer.
You do not have to adjust the BIOS again to boot on the HDD since the CD will not be present.
The above advice is from JoseIbarra.
post back and answer a few questions please, make and model of pc, current antivirus, OS and service pack.
http://answers.microsoft.com/en-us/windows/forum/windows_xp-system/invalid-bootini-file-message-when-starting-windows/1b329eec-ec6e-e011-8dfc-68b599b31bf5?tab=MoreHelp
also read the above thread please.