incresaing the root filesystem size?
 

I am stuck since my root file system is full on my PC.
I have windows in the same box in the 1st partition and the last partition belongs to linux. i kept second last partition for swap. In between windows and swap partition i have space which i want to allocate to linux root file system. are there any utilities which help me merge those partitions with /root. If yes, what will happen to the swap partition which is in between the new partition and the root fs?

It is not clear what distribution you are using. If you are using one with Gnome desktop, you can use Gparted.
But I tried Gparted to reduce the size of windows partition that Vista was not able to and now Linux is unable to read the table correctly.

You could boot up using a live distro. Using gparted, delete the swap partition, create a new one just above the XP partition. Then move down the beginning of the Linux partition and resize it to include the remaining space.

you can use parted magic, download the iso and burn it to a cd, make sure your first boot location in bios is the cd rom and parted magic will load to your ram. once its started and running the parted icon is on the desktop. if i'm correct most distros that can run live will have parted on them. i'm not entirely sure what will happen to swap partition but in parted you can move partitions around and resize them.