how can I recover without a repair install

I'm not sure although I know you can repair from the install disk if you want to do it that way, you boot from the winxp cd then hit enter when it asks if you want to install winxp then hit the f8 key to accept the agreement. From the next screen you are going to hit the "R" button to tell the installer that you want to repair your current version of windows, this should fix your problem, although remember that repairing your os will remove any updates and service packs that were not on the install disk, you will have to reinstall all of those.

it doesn't give me the 'repair' option on that screen.

while in the recovery console, try using "fixboot c:", "fixmbr c:", and/or "bootcfg /rebuild".

Running "chkdsk /r /f" never hurt anyone either.

at the cmd prompt type in chkdsk /r press enter
once done
take out teh xpcd ype in exit window will reboot
now tap f8 continously  before it can load  in the advanced options this time choose last know good config that worked. press enter

Or tap f8 continously  before it can windows loads log onto safemode yoru account press eneter if asked for a pasword.
In safemode desktop
r/click my computer properties advanced start up and recovery>settings>edit
check your boot.ini anything after>> /fastdetect ????  no exit or some such   take this back using your curse backspace until your boot.ini ends with    /fastdetect  

save the changes and reboot.

example of my boot ini with one partition and using xp pro
[boot loader]
timeout=6
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" /fastdetect


also in safemode

go to start manue run type in msconfig press enter go to boot.ini and make sure none are ticked to check all paths.

sorry about the spelling damn ehehe hope you read between the lines