XP fails to boot, only boots in safe mode

I ran PC Power Suite's Registry Defrag and Optimizer a few weeks ago and after the restart Windows XP will fail to load immediately after the loading bars screen and causes my PC to restart. It then goes to the boot up options screen and the only choice that won't bring me through the same process I explained above are the safe mode options. Once in safe mode it asks if want to do a system restore. I twice tried the system restore to no avail and now system restore is permanently turned off. I would try to reinstall the operating system but I don't know where the cd is. Anyone think they could help?