Would installing an OEM version of windows 7 on a laptop--specifically
The HP G61-320US interfere with any proprietary hardware?
OEM means is that the license is tied to the original hardware, so you can only install it on the machine it came with. However, there is nothing physical (or electronic) that will stop you installing on some other hardware.
I suppose there might be some HP or DELL or Acer specific drivers, but from what I remember they shouldn't interfere with the installation.
However, I assume that this copy came with some other (non HP) machine, so by installing it on the HP laptop you are breaking the terms of the OEM license.