Re-do of Partitions on a Hard Drive

I am about to build a new computer that will have Windows 7 Pro 32 bit installed. The hard drive I want to use is a 1TB drive with three partitions. C-drive is 100gb D-drive is 450gb E-drive is 450gb There is NO date on any of the partitions of importance so losing any data is NOT an issue. *How do I get back to a single partition so that I can then repartition the drive the way I...