Well, Win7 takes three primary partitions when it's installed -- and you can't mess with them without causing yourself a lot of grief. If you want to install Linux alongside Win7 you can only use logical partitions for the Linux side of the world; e.g., root, swap, home, etc. And, of course, you would have to shrink the Win7 side to give yourself a large block of disk space to logically partition and install Linux.
So, if you had an already installed Win7 and fiddled with any of the existing Win7 partitions... uh, you probably blew it and you'll need to reinstall Windows from scratch (then wait through over 250 critical updates, oh, joy). I don't remember what the names of any of them are (because I wipe Win7 completely, install Linux and then, maybe, install Win7 in VirtualBox; save a whole lot of time and trouble) but somebody with a "real" Win7 machine might be able to tell you (won't do you much good if they're gone, though).
Now that I think about it, maybe that would be a good alternative, if the thing is all messed anyway, to do a complete rebuild -- partition you drive completely with a, oh, I don't know, 50G - 100G partition for Win7, install VirtualBox (pointing it at that partition) and do a full install of Win7 as a virtual machine? Otherwise you're probably going to have to start from scratch and reinstall Win7. This because you're not able to use any of the Win7 "fixit" tools which is a good indication that the tools can't find what is needed to get everything back -- you do want to install Win7 then install Linux after it (just be aware of those three primary partitions that Win7 will create and remember that you will use logical partitions for Linux, you can look at the drive with cfdisk to see what they are if you're curious).
There might some way to fix it without reinstalling but I don't know what that might be; essentially, I won't all Windows on the property and only maintain one copy in VirtualBox. Hopefully you didn't blow it beyond recovery (somehow or other).
Hope this helps some.