part of the problem here is that there are 2 ways windows references a physical partition on a hard disk.
The first that occurs during the initial boot up process is the one that is stated in the boot.ini which will look something like this
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /NOEXECUTE=OPTIN /FASTDETECT
This is the absolute partition reference generated by the windows install. in your case if you deleted a partition preceding the one with your windows install.. like the following example
{ [ empty partition 1 ] [ Windows partition ] } => { [ expanded windows partition ] }
Would have the following entry in the boot.ini file.
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Microsoft Windows XP Home Edition" /NOEXECUTE=OPTIN /FASTDETECT
Following this example.... the boot.ini file would have to be changed. the partition number is no longer 2 it is now 1.
That is the first problem but that alone is not enough to correct the problem. Also in the windows registry there is a location containing a table that references partition ID's to drive letters. The only drive letter that is NOT changable is the system drive letter.
http://support.microsoft.com/?kbid=223188
Contains additional information on how to change it using the registry editor, which for you to get to in your situation will be extremely difficult.
This is the second place that this information is referenced.
I would initially try running the XP install in repair mode. it will correst the boot.ini file if you are not familiar on how to do that any other way. If the second issue is also a problem, you will have additional issues after the reinstall. If you can I would do a reinstall on a seond hard drive.