WinXP 32Bit IE 7 novice needs guidance to work through issues

Dell Desktop Windows XP 32 IE 7 no free memory to download anything. Can't remove programs, no security tab. No windows installer in safe mode. I've confused myself now.
Cannot access any file due to permissions. Need to know how to remove programs, then reset permissions. I've been trying to work on this for two days. Can't seem to make sense of any of the great information and tools available, because I don't know which to address first.

Why not copy out your files and run Dell Factory Recovery from it's partition? Dell Restoring Your Computer´s Software to the Factory Settings

Make your Recovery disks first so you have a backup method.

I'd first check the hardware with Dell Diagnostics Utility - How to Run the

If this fails you can run an XP Repair Install.

With the XP SP3 installer for your licensed verison on COA sticker, you can also if necessary move on to Clean Reinstall if all else fails. Or you can buy Win7 upgrade version to Clean Install Windows 7

Thanks for the information. I will give this a try tonight. Appreciate very much your sending the links to each step!