Help with changing Windows partitions and booting them

Short:

The Windows 7 x64 I use is on another drive than the MBR and Windows Start Manager. It further is the second partition (of 60GB and 170GB) on that SSD. How can I get rid of the first partition there, extend Windows to use the full SSD and boot directly from there without the other drive being needed anymore?

Long:

I've quite some partitions and versions of Windows on my internal harddisks. (Trying out new OS and adding them on a new partition the system just grew this way.)

Harddrive 0 contains the MBR, Bootmanager, a 300GB Partition of Windows XP and another 260GB Partition. Lets call this partitions A and B.

Harddrive 1 has Data

Harddrive 2 is an SSD and has a 60GB Partition of Win7 32bit, and a 170GB Partition of Win7 64Bit. Lets call this partition C and D.

Currently my PC starts up the bootmanager and (if I dont choose otherwise) after a few seconds it boots Partition D (Win7 64bit) which works fine.

To make things simpler and free up space I want to get rid of A,B and C and just use D (Win7 64bit) directly, as I dont use the other OS/partitions anymore.

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What is the easiest/best way to get there?

Thanks for any help, really appreciate it!