When ever you install any program, by default it gets installed in your C drive thus reducing the size of C drive. And when it is filled users start getting annoying balloon messages at the taskbar saying Memory is too low....
So to overcome this problem here is the solution to it :
>> Go to your D or E drive and create a New Folder and name it Gagan.
>> Now press Windows+R and type diskmgmt.msc and hit Enter.
>> A new Window will pop up named Disk Management.
>> Right click on (C:) and select Change Drive Letters and Paths. For help
>> Now click on Add and browse to the Gagan folder created in first step and click OK. For help see this screenshot
Thats it !! Now size of the C: drive is increased and in future you will not get any message about low disk space.