Macbook major issue

I have a macbook with version 10.4.11 on it and one day it decided that nothing will work on it....heres what i mean when i try and open ANY file or program or software i get "there is no default application specified to open the document" that goes for the web if i try putting a disk in it will act like its doing something then just spits the disk out.....is there a way i can either A. reset to factory with out any disks or B.put windows XP on it for now,

ty in advance for any advice

P.S ONLY Skype works on it,will not detect internet or anything i have opened EVERY possible file that i see and nothing BUT skype works

anyone have any idea's?

Try repairing the hard drive. Use one of the three methods here:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck