Annual PC Checkup

At least Anually the following procedures should be followed
Beginners Guides: Annual PC Checkup Checklist - PCSTATS.com

Decent guide, except that it was written 3+ years ago. There are some flaws to it, that can get the average user in trouble like:

Oiling a fluid-bearing fan?
Not using compressed air to clean the fan blades (why not just hold them in place?)
Defragmenting your HD (not a very good idea if you have an SSD(s) installed....

These are only the issues I saw when skimming the article. There is a reason computer kits are not $49.95 at your local radio shack - modern day machines can be expensive beasts, and allowing a novice user to get inside can be a dangerous thing.

Being a tech myself, some of the things I have seen happen:

1. When trying to clean CPU heatsink/fan combos, ppl have broken one of the mounts, then thought to themselves "Hey, it's still got 3 of them, it should be good." Wrong!
2. When trying to clean dust bunnies out of the computer, they forget that their computer is in 'sleep / hibernate mode - and it powers on as they accidentally bump the mouse / press a key right when the vacuum cleaner hose is making contact with the mobo....
3. Power wires get unplugged and then they forget to plug them back in and then you get a system fail (particularly with CPU heatsinks)

You really need to have a basic understanding of the hardware inside your computer before jumping off on this project. Paying $200 for cleaning is outrageous, indeed, I charge ~20% of that, but I'd rather you pay me $40 to do it right after researching your computer than doing it yourself - and then paying $200, $300, or even more to repair parts of your computer / the computer itself.

TY for the comments which are now part of the record and can help others.