I had Windows 7 installed as my main OS. Then I created a small partition on the same drive. I put in my XP cd and began installing it on the new partition. It then restarted the computer and when it tries to boot the HDD I get "A disk read error has occured. Press alt + ctrl + del to restart".

I know my data is intact...but I have no clue how to access it.

Some more backstory: I was eager to install XP on a separate partition and was too naive to google about bootloaders and such, wasn't aware they were necessary, which is why I'm in my current situation. If I could just access my Windows 7 install I could probably use a bootloader to fix it all up.

Anyone have any ideas on what to do?

usually popping the windows 7 install disk fixes this problem fairly easy - assuming its not a hdd failure, your Master Boot Record is corrupt

pop in the windows 7 install dvd - select repair - it should search end detect your win7 install and prompt you for next to attempt repairs