Not usually, unless you totally arse something up. (Unlikely).
- It depends on the media you are re-installing Windows from possibly.
- If you are using OEM or Retail Windows 7 media then it should be fine.
- If you are using a PC brand recovery media then it might wipe everything and go back to a 'factory defaults' state.
If your Windows is on C:, then just make a back-up of everything on C: --- much faster than everything on every volume/partition and re-install either over the top or delete the C: partition (afterwards) and do a fresh installation.