system restore

SR does not always work. Once it malfunctions, "RESTORE INCOMPLETE" the program is useless. As an alternative I downloaded COMODO TIME MACHINE. The issue is that despite the "DO NOT TAKE SNAPSHOT" choice I made, I run out of FREE space from my small hard drive. I do not know how to reformat or reinstall XP once I have replaced the hdd. I do not happen to have one from another tower that will work with this tower a DELL 8100. Lately CTM has been having issues with the rest of the system. I tried to uninstall it from add/remove. Error mess "FATAL ERROR IN INSTALLATION". I could only remove it from the "HOME" key during boot. CTM works fine on my other 81. I tried to reinstall it and again I got the same FATAL error message. Is there a FREE SYSTEM RESTORE program for XP similar to the built in program that would be better isolated from outside bad guys? I looked at programs but they all looked like more than I need or I did not understand them. What I want is a program that will NOT take restore points if I choose. My thinking is that when the system exhibits issues, I can restore it to the point of installation when the system was "CLEAN". I do not mind reinstalling programs lost. I do not save much data so that is not an issue. I need recommendations, web sites, links. Thank you.

 

One more wrinkle. I tried your instructions and the only indication of any change was the "KEYBOARD FAILURE" error, and the fact that my mail client had reverted to an earlier layout. NO control panel or other screen appeared. Also the optical mouse did NOT work AFTER the key press and including the os reload. I needed to revert to a track ball, shut down, reconnect optical. That worked. Why the DELL instructions did not produce any screens I do not know. I can only presume it worked because of the mail client layout change. I may or may not try CTM again on this tower. I do not know whether this will affect a healthy install.