Reinitialization?
 

I am not a programmer, but have been an Ubuntu user for 3 or 4 years. It seems that I need to clean up my system. Would like to low level format, and start all over. I also have a lap-top that I would like to restart. How do I/can I do that? Thanks.

Not sure what you mean by "clean up" your system, but the customary procedure is to save your data to an external drive and install all over again, usually with the latest version of your favorite distro.

I doubt if you need to do anything of the sort. Do you install new versions of Ubuntu or do an upgrade? (Does Ubuntu offer an upgrade? I've lost track, as it no longer runs on my hardware). If you do a clean install, then that takes care of the software. As for /home, that may accumulate a few obsolete configuration files, but they just sit there doing nothing.

Windows systems need cleaning up because the registry can get disordered and the filing system can get fragmented. Neither problem is relevant to Linux.

Low-level formatting is pretty much obsolete these days. See this Wikipedia article.

Hi I'd either follow Albinard's advice and delete all partitions using a live or the install medium then install to free-space or DavidMcCann mentioned:best wishes and have fun. :)

Thank you all for the guidance on how to proceed. Reinstallation seems to be the way.
A question I have is about the laptop: It came with proprietary Windows 7, and when attempting to boot up, I see three critical error messages: "Hard disk boot sector reading error", and "System blocks were not found", and "Error 0x000000050 -Page fault in non paged area" Is there anything I can do to save this HD?

Honestly, don't even try. Hard drives are so cheap these days that taking a risk on a flaky drive is more trouble than its worth. Shove it into an external USB enclosure (which are typically less than $20), if you must, but on your day-to-day system, don't take chances.