Need to Remove System Partition on Dual-Boot Laptop

I just recently received a dual-boot laptop that originally had Vista but is now running Windows 7 Home Basic - it will no longer boot in Vista. This computer has a single hard drive that is partitioned with the C drive (Vista) having the bulk of the storage and only 10GB are left for the partition with Windows 7 (the D drive). This makes the computer run very slow and there is no space to install many programs.

http://www.sevenforums.com/attachment.php?attachmentid=172214&stc=1&d=1314387860

What I want to do is get rid of Vista, the partition, and everything currently on the C drive so that I can use the whole hard drive with Windows 7. But I see that System files are on the C drive and don't want to format that drive and completely mess up the laptop. Is there a manageable way to accomplish this without having to reinstall Windows 7? I am by no means a computer guru and any help would be much appreciated.

Thanks.

Take look at this tutorial:
http://www.sevenforums.com/tutorials/109752-partition-recover-space-used-older-os.html

That looks perfect! I'll try it out and update the results later.

Thanks!

Uh oh. After marking the Windows 7 partition as "Active", I tried booting to system recovery options from a repair disc but I am getting the message:

"BOOTMGR is missing
Press Ctrl+Alt+Del to restart".

and the laptop won't boot.

Do a Strartup Repair:
http://www.sevenforums.com/tutorials/681-startup-repair.html?ltr=S
Note: You may need to do startup repair 3 to 4 times.
http://www.sevenforums.com/tutorials/105541-startup-repair-run-3-separate-times.html

You're not yet booting the Repair CD. Set it first to boot in BIOS or use the one-time BIOS Boot Menu key given on first boot screen.

Accept any offered repair. If Win7 doesn't start, boot back in to run Startup Repair up to 3 separate times with reboots.

The problem was my repair disk. I found another one online and everything worked great. Thanks for the help!

You are welcome.