Sounds like if you've already gotten to the product key screen that your machine has either been reformatted or you're doing an upgrade which I would not recommend ever. Also if your keyboard becomes unresponsive it would appear that XP does not have your keyboard's specific drivers in it natevily (pretty common) so that's why it becomes unresponsive. It'll work for a bit then stop? That's because when XP goes to verify that it has the correct friver for the keyboard it realizes that it has a generic keyboard driver but not the right one for you so it turns the keyboard off.
If you have another computer available I would strongly suggest you download Nlite
http://www.nliteos.comNlite allows you to create an unattended XP or Vista install disc. Basically what you do is run the program, it reads your XP disc to get its base and then it lets you add on certain things like CD key and drivers.
1. Download Nlite
2. Download the drivers for your laptop from the maufacturer
3. Insert your XP disc
4. Run nlite
5, Integrate your machine specific drivers
6. Make whatever tweaks you want (you'll understand when you get to the screen)
7. Enter your CD Key
8. Burn customized XP disc
9. Let it run by itself in the laptop
10. You're done