You have bigger problems now by converting the HD to Dynamic Disk which is meant to span partitions across multiple HD's not on the same HD. This cannot happen without ignoring clear warnings that this will happen with dire consequences. Why?
You can use PW installed version partition wizard 4.2 free.zip
to unzip, install and then follow these steps to convert dynamic disk to basic disk with Partition Wizard.
In the process you've also shifted the System boot files from the System partition into C, which may be causing the Boot menu issue. I would delete that partition, resize C to the left using Partition Wizard bootable CD: http://www.partitionwizard.com/video...partition.html
Then rebuild MBR since the boot sector has been resized. Have the Windows 7 DVD or REpair CD standing by if necessary to run Startup Repairs as well.