Hi
I can understand your reluctance. It's not for the faint hearted however once you realize what's involved its not difficult at all. You can google for yourself as there are variations of the same theme. However an excellent resource is here:
http://discussions.apple.com/forum.jspa?forumID=599
What you could do is use the built-in CD/DVD Burner and backup any pertinent data. Make a note (write them down) of key settings for mail, passwords etc. Better still purchase an external hard drive. I would recommend you do this anyway for backup purposes. Something I feel sure you regularly do? You could 'clone' (an exact bootable copy) your existing drive onto that. Test it before going any further by booting from it. When you're happy insert the Installer Disk that came with your mac, boot from it, select Erase and Install. Once installation has finished restart, create your account exactly as before. Re-instate any pertinent network settings for internet access etc and get it fully up to date. When you're happy attach the external drive and use Migration Assistant to transfer what you want thereafter.
You could do this manually using the external drive. Drag/drop pertinent data: Music, Photos, Mail etc to the drive. Once you're happy continue with the Erase and Install. Copy back when you're happy. Install any additional Software using the installer disks.
I would also search the Forum as it is a subject that has been tackled many times. Perhaps you failed to notice the three links listed at the top of this Forum page? This one is probably relevant:
http://discussions.apple.com/thread.jspa?threadID=1772235
Seeing as there is actually nothing 'wrong' with your computer you could simply ignore this advice? Remember all advice is not necessarily correct for you or your situation. It's a good idea to wait and see what others have to offer so as you reach a balanced judgment.
You could hone your skills with a 'test' backup and reformat and reinstall once you're certain your cloned back up works. Once you've refined your skills clone back again. You've lost nothing yet you've gained a skill you did not have before plus added confidence.
Simply shutting down your mac 'cleans it up' to a certain degree. The OS does its own housekeeping on shutdown. Something that most people who leave theirs on 24/7 fail to realize.
Tony