Switched hard drives

Change the boot order in the bios.

As the recovery drive is usually a second partition, rather then a seperate physical drive, some more information would help.
What is the size of your recovery drive? are you shure you have 2 physical drives, what was the original OS and explain the steps you used to install Windows, because I suspect you have installed on the recovery partition.
Disk Managment will show if it's 2 drives or one with 2 partitions.

recovery is 9.99 GB os is 136GB. I bought the windows 7 cd and put it in the dvd drive and followed the instructions on the screen, the recovery drive is now the( C  and the os drive is( D  I have a dell inspiron 1720 laptop. It had windows vista home premium and I up graded to windows 7 home premium.

I would leave it as is. No need to change it, mine is running on F: without a problem.
I was concerned you may have used the recovery partition to install on, but all looks well.
The instalation of programs won't be affected, they will still install on your OS drive D:
I'm don't know what sort of problems you may run into trying to change it. I say, if it ain't broke, don't fix it.