Changing the System Volume

I got a Lenovo T61 a couple of years ago which came with Windows Vista, but later I bought Windows 7 and installed it on this computer. Now that I'm not using Vista, I'd like to delete it and possibly allocate some of its space to my Windows 7 partition and create a new one for Ubuntu. Is this at all possible? My Windows 7 installation is on a drive called Z:, and Disk Management shows it as 'Healthy (Boot, Page File, Active, Crash Dump, Primary Partition)', but C: is both 'System and Primary Partition'; I suspect that it's 'System' designation is preventing it from being either formatted or deleted. When I try to format it, I get the following error: Format is not allowed on the current boot system, system, pagefile, crashdump or hibernation volume When I try to delete it, I get the same error. Does anyone know what I can do? Thanks.

Even though Windows 7 is installed on Z:, files it needs to boot are on C:, thus you are not allowed to format C:. If you were successful in getting rid of C: and merging the space into your Windows 7 partition, Windows 7 would no longer boot as it expects everything to be on Z: and once you delete the existing C: I believe Z: would become C:. The only way to do what you want that I'm aware of is to save your data then reinstall Windows 7, taking the Custom path. Then delete all existing partitions and repartition the drive so you have one for Windows 7 and one or more for Ubuntu.