Please help blue screen on Windows XP Pro

Hi everyone... I'm having problem with my dad computer hopefully someone could help me. Startup has bluescreen and won't be able to access the computer at all. Please, please let me know what to do. Are we going to lose the files if we fix it?

Thank you so much.
Melai

We need considerably more information from you in order to help.

1. Give us your hardware specs including make and model of motherboard, make, type and amount of RAM installed, vide card, etc.

2. What security software are you running?

3. How old is your system?

4. What error code does the bluescreengive?

5. How long has this problem been going on?

6. Was there anything downloaded and/or installed recently?

Sorry, double post.

Route44,

Sorry I don't memorize all that info and I can't access the computer right now, but here's some info might help
Computer is Dell XPS, about 3 yrs old,windows xp pro, the problem is been going about two weeks now nd I believed my dad downloaded somethin big from internet. Pleasee let me know the steps on how to fix my ad computer, I really apreciate your help.
This the error code...
driver_irql_not_less_or_equal
tech info: stop: 0x000000D1 (0x00000018, 0x00000002, 0x00000000, 0xB9E4525F)

That 0xD1 is usually caused by a faulty driver. If this occured after whatever your dad downloaded is a good bet therein lies your issue. Find out what he downloaded.