You don't mention any other OS's, but let's assume you have Windows 7 since you posted here.
Boot into Windows 7 DVD, select Repair My computer on second screen, then click through to Recovery Tools and run Startup Repair up to three separate times to repair or recover the Windows 7 boot.
When you get Windows 7 started, post back a screenshot of full Disk Management drive map, using Snipping Tool in Start Menu.
If Windows 7 will not start after running DVD Startup Repair 3 separate times with reboot, burn to CD bootable Partition Wizard
, boot into it, choose 1 for screen resolution, then right click Windows 7 partition to Modify>Set to Active. Apply steps.
Now boot into Windows 7 DVD again and Run Startup Repair up to 3 separate times to start Windows 7 and post back Disk Mgmt screenshot.