The question is, why do you want to delete it? Do you know what it is and what it's for? It sounds like you may not know. Do you want to delete it because it's a big file and it's taking up room on your hard disc?
The answer is that the pagefile.sys file is the Virtual Memory file for your computer. Your computer uses it when it doesn't have enough RAM left for running programs and data. It swaps out some of the RAM data to the page file and then reuses the freed up RAM.
If your computer has more than 1Gb of RAM, you can tell the system not to use any Virtual memory (which will delete the file) but usually it's not a good idea to turn it off completely as you may start to get "Out of Memory" error messages and Windows or other programs may start to crash as not all programs handle "out of memory" situations gracefully.
To atain and maintain good system performance, make sure your machine has at least 1Gb of RAM (more if you use big programs or process large quantities of data (e.g. large image/audio/video file manipulation, CAD etc) and at least 5Gb of free hard disc space (more is always good). Upgrades nowadays are cheap and well recommended.
If you still want to delete the file (or shrink the amount of space it takes up) follow these steps:
1. Right click on "My Computer" and then click "Properties".
2. On the resulting "System Properties" window, click on the "Advanced" tab and then the "Settings" button for "Performance".
3. On the "Performance Options" window, click the "Advanced" tab and then the "Change" button in the "Virtual Memory" section.
4. Click on the C: drive and then click on the option for "No paging file" and then hit "Set".
5. Click "OK" all the way back out and Restart the system. You should find the pagefile.sys file is gone.
But as I said before, it's not a recommened option as the system needs a paging file to handle low memory conditions.
If possible add a paging file to one of the other partitions (if the machine has any).
If you are running out of disc space, do a "Disc Cleanup" (Right click C:, click properties and then Disc cleanup - delete all temp files), uninstall unwanted programs (Control Panel/add-remove programs) and documents etc.
You can also disable hibernation (check power options under the screen saver section) to free up disc space as the hibernate file takes up disc space too.
Or if you have already done all that, add another hard disc for storage or upgrade your existing one.