Our computer has a 6g hard drive and I just reformated it a couple of days ago. It had been running slow and saying that it had low disk space. So after I reinstalled Windows XP and as I was installing the various drivers I was watching to see how much disk space was left empty. It had like 2.5g of free space. Then today I noticed that it was back to about 415 mgs of free space left. So I deleted all unnecessary programs which leaves it with just the drivers, the virus protector, web browers, flash player, and some files that look like they are necessary for Windows. That adds up to less than 300 mgs and there are no documents or pictures on it yet.

I downloaded and ran WinDirStat and it looks like what is taking up the most space (other than Windows which takes up half of the space) is a file called pagefile.sys. Can anyone tell me what this is and if I can safely delete it? Thank you for your help.

You won't get read of pagefile that easy. Pagefile is a file that "extends" your pcs ram. When windows don't have enough memory to store data, they write the data that won't fit into memmory into the pagefile, thus "extending" your ram.

I doubt that you can delete it, as it will be in use all the time (unless you boot from a usb or a cd/dvd and delete it), but even if you do windows will just create it again.

Solution 1: Buy a new HDD?
Solution 2: Compress your exist HDD? WARNING: This will slow down your pc, as it will need to extract the files before using them.
Solution 3: Compress folders that you (including windows) don't use often. WARNING: Again, this solution will slow down your PC, but not as frequently as the above solution, as you will be compressing folders that you don't access that often.

From your description I guess you won't see much change using solution 3.

Actually you can disable pagefile.sys in Windows XP.

Pagefile.sys is actually a virtual RAM which if RAM are insufficient for programs to run, they'll used virtual RAM within hard drive disk space (pagefile.sys) but it'll process much slower in virtual RAM rather than actual RAM itself.

If you have at least 512MB of RAM and you don't run much program, music or video, then pagefile.sys can be removed although it was not recommended.

Follow this instruction to remove pagefile.sys

- Right-click 'My Computer' and select 'Properties'

- Click on 'Advance' tab and click 'Settings' under 'Performance' box

- Under 'Performance Option' window, click 'Advance' tab. There should be a 'Change' button under 'Virtual Memory' along with total value of pagefile.sys. Click the change button.

- Under 'Virtual Memory' window, there should be an option 'No paging file'. Select it and click on 'Set' button.

- Exit all open windows with 'OK' and restart windows.

After this, there will be no pagefile.sys existed in your system but you'll see a slight decrease in computer performance due to stress put on RAM only.

Hope this helps... ^^

It can actually. You need to disable it first with from the post above and reboot, only then you may delete it.

Try using force delete if you still can't delete it after disable pagefile in windows.

I'd let Windows have a 50MB pagefile, fix it at that via the task.
A 6GB hdd? Windows, fully updated and with drivers loaded, is going to want roughly 5.5GB of that. Another browser and things start to get tight.
IS the sys running well? No idiosyncracies? Then open the Windows folder; go Tools tab, Folder Options, View tab - chhose to Show Hidden files and Folders. Right, now inside the Windows folder you see all those blue folders? Delete them all. LEAVE the $hf_mig$ folder UNTOUCHED. [those folders in blue are there in case you wished to reverse a KB article package, such as an update or security fix; if your sys is running finely then you don't need them.]
There are a couple of great guides on the web which ask you searching questions about your use of just about every Windows file/folder/service with a view to deleting them. Believe me, there are literally hundreds of such things for the average user to delete with no ill-effects. eg. do you really wish to keep all those desktop backgrounds/screen savers or bits of sys music or that helper dog or the guide to using windows or arcane services or....

Windows XP will create a page file even if the user manually deletes it.
The manual deletion option is to enable relocating the page file to another drive or partition, not to delete the page file as a sub-system
Regardless of total installed ram memory , Windows is designed to use a page file and will store data on that

An absolute minimum 2MB is mandated however if there is not enough , Windows memory manager will create additional space in real time , which is a certainty.

To assist user disk storage management you can configure a nominated size to fix the page file location and stop being fragmented - 1024MB minimum, 1024MB maximum should suffice, keeping in mind windows will notify if not enough
(I do not suggest this for VISTA/Windows7 users)

http://windows.microsoft.com/en-US/windows-vista/Change-the-size-of-virtual-memory