I have 2 hard drives in my computer, and used partition magic to partition my main
300 GB hard drive in half so I could run 2 operating systems – I partitioned fine, but when I went 2 install windows xp on my new partition, I accidentally formatted and installed it on my secondary hard drive that had 177 GB of files on it.

Is there a way I can undo the installation and format and recover all my files?
I should have paid closer attention, but I didn’t – and I really need some of those files (most of them) so I hope you don’t think m to nooby and if you could help me that would be awesome.

Yes, recovery is possible (RIP).

EXTREMELY IMPORTANT: do not touch, look at, explore, run, or change any files/folders on the second hard drive. All your files are always on the hard drive until you write something on top of them. Don't use your new Windows installation. Don't run scandisk. Don't defrag.

Tool: TestDisk
Download page: http://www.cgsecurity.org/wiki/TestDisk_Download
Wiki page: http://www.cgsecurity.org/wiki/TestDisk
Quick (slightly outdated) Guide to using the program: http://mirror.href.com/thestarman/testdisk.html

Download and run TestDisk (win/testdisk_win.exe, no install needed) from Windows on your first drive. You want it to analyse your second drive. When it finds your deleted partition (you may need to give it some hints), restore (write to disk) that partition. Reboot and with luck everything will be back the way it was. You might end up missing a bunch of data equal in size to the Windows installation.

Tip: When you need to make important changes to a hard drive or are installing a major program (like an operating system), unplug the other hard drives so there is no chance of acciddentally messing them up