Changing drives for Windows 7?

Hello, I have recently installed Windows 7, and due to my having Vista Business, and buying Windows 7 Home Premium, I could not just upgrade, I had to create a separate OS. Anyways, I installed it into my (D drive, not sure if I could put it in (C. Turns out, it only has 9.99 GBs, and Windows 7 takes up almost all of that, leaving me with about 300 MBs free. Well, obviously that is a bit of a problem. So my question is: can I transfer my Windows 7 to (C, with or without re-installing it?

Thank you!

sarfraz, welcome to the forum! Can you type (in your Start Menu) " Create and Format disc partitions"? This will allow you to "shrink" your Vista install, so that you can use Windows 7. Or, use another partitioning tool to do so? A tip here, make sure that your disc has been defragmented first. If you need more help, post back.

Turn on your computer and your Internet connection. Your Windows 7 Upgrade will use Internet access to receive updates during the installation.
Place your installation disc in your CD-ROM tray or double-click your downloaded file if you ordered Windows 7 online. Keep your Windows product key handy.
Click "Install Now" when prompted once the installation file opens. If your computer is connected to the Internet, select "Get important updates for installation," and download updates. If you are not connected to the Internet, skip the updates screen.
Read the Windows 7 licensing information, then select "I accept the license terms" and click to the next screen. Select "Upgrade" as your type of installation, then hit "Install." Allow Windows 7 to install completely. Do not power off your computer during the installation. Once it is done, restart your computer

Yeah that is right. Please make sure that that your system do not get powered off else it may lead to data loss situation and in that case you will have to use a windows data recovery software.

Welcome davison. Hopefully, I'll help you in future.