Have a look at these two articles:
Windows XP is not the best option for running on an SSD drive.
Trial Software "FolderInfo" will search for folders/files over a specific size.
Also check Doc's & Settings/Application for large leftovers from any Video or Burning sofware.
Three things you can do to gain a bit of free space on either XP or Win7:
1- Run "Cleanup" by Steven Gould, excellent multiple profile cleaner.
2- Run "CCleaner" by Piriform, great single profile cleaner with free Registry cleaner. Run the cleaner and the Registry tool.
3- Assuming your machine is otherwise running fine, turn off "System Restore" (XP) "System Protection" on Win7. After it's done, turn it back on. Set only as large as need be about 10% is sufficient. This is where you gain at minimum 6 GB if it were turned on.
4- How much memory do you have installed? By default, Windows allocates 1.25X the amount of memory towards the system Swap File. So, if you have 4 GB of memory, you are using 5 GB of diskspace. 2GB of Ram uses about 3 GB of disc space.
If you have 4 GB of ram, you can run without a swap file. I have 4 GB of Ram on this Win7 LT, with an Intel 80GB G2, with NO swap file. It's run fine w/o the Swap File and is plenty fast.
*****Lastly, try at your own risk***** I run defrag about every 3 months IMMEDIATELY followed by the Intel Toolbox. Could be my imagination, but it seems to run out-of-the-box FAST again. My G2 drive is now 2-3 years old, so I don't care if it shortens the life at this point. It has NEVER bluescreened on me EVER, never lost any data.
There is absolutely no reason to run a defrag on an SSD, in doing so all you do is wear it out quicker.
Defragging on a hard-drive is necessary because it is mechanical so you want to move files close together (even then it's debatable whether defragging helps that much), but as an SSD is electronic, it doesn't matter where data is on it as electrons move pretty fast!
Due to wear-levelling on an SSD, data is deliberately chopped up and written in different places. If you defrag an SSD, the operating system provides instructions to re-write the file into one place and the SSD simply says "Okay I'm doing that", but under the bonnet it is completely ignoring the request and just putting the file where it wants to spread out the wear and tear. You've gained absolutely nothing except perhaps a nice 0% defragged pie chart in the software you are using and the placebo effect of doing a defrag, in reality nothing has been optimised on the SDD as it doesn't require defragging, and you've just reduced its life span by a bit.
I suspect it is the Intel Toolbox optimisation that is causing any real performance improvement.