If that hidden partition at the first of the HD is EISA, it will require a special DISKPART Force Delete Override command to delete. Try Partition Wizard first.
If not EISA, then all 5 can be easily deleted as suggested by using the booted Windows 7 DVD Custom>Drive Options, then create New and Format before install.
You might want to make your Recovery Disks first in case you ever want to return to Factory condition to sell or service warranty. Is it Vista on there now? If it's Windows 7, then you need a clean copy Windows 7 DVD of your version to clean reinstall - using Restore disks will just recreate all the partitions as from factory.