Its not possible to increase ur memory size but u can compress ur data to save ur disk space, this feature is available in NTFS drive. if u have a fat or fat32 drive, u can convert it to ntfs by running a command on dos.
for c drive:
convert c:/fs:ntfs
for d drive:
convert d:/fs:ntfs
for e drive:
convert e:/fs:ntfs
run the command similarly if u have more drive...
Compresing data in NTFS
1. open my computer
2. select any drive(drive with NTFS format)
3. right click and select properties
4. click on general tab
5. select "compress drive to save disk space"
Apply and OK
