If you are able to get into Windows check your Boot.ini file and see if anything has been added.
Press the WinKey + Pause/Break, Advanced System Settings, Startup and Recovery, Settings.
When you are in here you can select Edit to open your Boot.ini. It should look like this if you aren't dual booting.
eXample:
Standard
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows XP Professional" /fastdetect
If you don't have access try this first.
Insert your XP CD and when you see ?Press any key to boot from CD? press a key. Now wait for the XP installer to finish loading up and you will be presented with the option to press R to Repair.
Press R.
The next screen will ask you which Windows? installation you would like to log on to. Normally the following will be listed:
1: C:\WINDOWS
Press 1, then Enter to continue.
You may now be asked for the Administrator password. If you know this type it and press Enter. If you don't know the Administrators password it may be blank. Just press Enter or type your username and password.
When you get into the Recovery Console you will be at:
C:\Windows
We need to change to the C:\> prompt
Type CD .. and press Enter
Type ren boot.ini boot.old and press Enter
Type bootcfg /rebuild and press Enter
Let it scan
Total Identified Windows Installs: 1
[1] C:\Windows
Add installation to boot list? (Yes/No/All)
Press Y and then press Enter
You receive a message that is similar to the following message:
Enter Load Identifier
This is the name of the operating system.
Type XP Access and press Enter
You receive a message that is similar to the following:
Enter OS Load options
When you receive this message
Type /fastdetect and press Enter
Type eXit to exit the Recovery Console
Restart the System and you will be presented with a choice of Operating Systems. Select XP Access.
