I have only C drive in my laptop. can i partition my c drive without losing my o

I have only C drive in my laptop. can i partition my c drive without losing my operating system (windows 7) and data?

Yes, probably. There are partitioning utilities that will work with a drive with OS and data. But to be safe, before using them, you should back up the complete drive to an external drive.

What you should do is defrag the drive, then image the drive to an external drive. I use a program called Acronis True Image - about $40. If you have a Western Digital drive, there's a free version tailored to WD drives on the WD website.
http://www.acronis.com/homecomputi [...] trueimage/

And there are other free backup programs.

This is insurance in case something goes wrong.

Then you can partition the disk. Again, I like Acronis:
http://www.acronis.com/homecomputi [...] kdirector/

And, again there is free software to do the same thing.

Then you restore the data.

Following jsc's reply, but for free alternatives, check:

Clonezilla for backups (which, as jsc said, is a good idea to do before
messing with partitions)
http://clonezilla.org/

Gparted for resizing/creating partitions
http://gparted.sourceforge.net/

I have used both products without any problems but I had to do a
small amount of reading on their webpages before (nothing too
hard though).

Both programs have to either be burned on a live CD (a cd that will
run on boot time, just like a windows installation cd) or installed on
a usb stick.