Black Screen with Cursor prevents booting to Windows

Hi Folks, I've got an urgent problem.

I have a relatively new Dell Inspiron 1564 with Windows 7 Home Premium 64bit on it. The problems started when I removed Dell's preset "data" extended partition (D:\). I then extended the C: partition where Windows is to the whole drive minus the recovery partition (which I labeled as R:\). A "bootmgr is missing" error happened until I made the Recovery partition as Active (which I thought was very weird in itself). But the laptop seemed to boot as normal.

Then, out of the blue, I turned it on and once past the Dell splash, a black screen with a blinking cursor on the left corner came. I couldn't boot into Advanced options (F8) or Windows at all. I tried using a recovery Windows 7 USB stick that I had and was able to get into System Startup Recovery but this hasn't worked to fix the problem. Messing with the cmd has not helped either. However, I can still get into Windows if I boot to the USB, because it shows "Windows 7 (Recovered)" in the boot menu, which happened after a Startup Recovery. So Windows itself seems fine, its just the boot sector that's messed up. I tried using Dell's recovery feature and reinstalled Windows on the C: partition but this didn't change anything. The problem seems to be the bootmgr is on the R: drive, not the C: drive.

I need to fix this very quickly so urgent help is much appreciated!

Yes.

Look at this thread:
Re-Install windows 7 boot manager

No I don't have the original DVD. I tried rebuilding the boot manager with cmd and Easy BCD but it did nothing. I've settled on just a full reinstall. I had a copy of Windows on hand so I reinstalled and everything is peachy. Dell's recovery partition is such a piece of crap anyway...

Now, I need to get a working activation code since the code on the bottom of the computer was too smudged to be useful. *facepalm* Would Dell be able to fix this? I'm wary of doing so since this isn't my computer but a client's.

If I do that won't it just give me the old OEM code? I have that and tried using that to activate the new install and it didn't work.