Thanks. Now we have some information.
You have an 80G HDD and all 4 primary partitions are already taken. That means installing any Linux "the right way" will entail lots of partition work first. This is not for the faint of heart, since it can leave your Windows system unbootable, needing repair.
I would strongly recommend using virtualization if you have a Core-2-Duo or better CPU in the machine AND at least 2G of RAM. There is good news. Seems you have plenty of space for a respectable Ubuntu/Linux install. With virtualization, you can put a 15G "virtual HDD" on the sda3 partition without risking Windows.
BTW, be certain to thank Dell for using all 4 primary partitions (4 is the max allowed under MBR partitioning), preventing you from easily creating any more partitions. The 1st and last partition appear to be Dell hardware utilities and a re-install Windows partition, but I don't understand what the 2nd partition is. Seems odd to me - and I've owned 4 Dell laptops myself.
/dev/sda1 vfat 32M 4.0M 28M 13% /mnt/boot-sav/sda1
/dev/sda2 fuseblk 300M 177M 124M 59% /mnt/boot-sav/sda2
/dev/sda3 fuseblk 71G 22G 50G 31% /mnt/boot-sav/sda3
/dev/sda4 vfat 3.5G 3.4G 17M 100% /mnt/boot-sav/sda4
If you want to move forward, there is a path to either Virtualization or Dual Booting. So - do you have a Core2Duo or better CPU with 2G of RAM or more?
Can you add another HDD to the system?
Can you 100%, completely, backup the HDD and are you prepared to wipe partitions, resize partitions, and recreate "logical" partitions which will allow much more flexibility? Definitely read up on MBR partitions at wikipedia first.
The first 2 options are much, much, much easier than the 3rd.
It is your decision now.