Hmmm... Can state some more information about your situation? Can you still access Windows XP and log in? Or can you only access safe mode? If you can not run .exe files please read this:
Cannot Run .exe Files
Yes, you can reinstall Windows by just taking your bootable disc of your operating system and sticking it in your system and reinstalling the operating system. Please state more though of your situation. Like how did you get this way? Can you access regular Windows XP? And other useful things.
Raistlin