If I do not install "Microsoft Genuine Advantage" am I missing security updates?

Yes, MS will hold back security patches from Windows Update until you install Genuine Advantage. There may be other ways to find and install them, but I don’t know how myself.

If your software is legit (especially if you have an invoice/receipt from it or the PC it came on) then unfortunately then best option is probably to install it. I think it’s very rare for it to mistake legit for not (I’ve not seen it happen at least).

(Or of course try Linux ;-) )

I think installing it is worth it. It always worked best for me. But you could also just install
AbiWord. Its amazing , and uses less memory. Its also free!

what is AbiWord?

AbiWord is a free word processor made from lunix and microsoft windows. It is very similar to microsoft word, but microsoft word tends to be better. What am I saying duh its better if you buy it , its 300 bucks! Uhhhh thats what it is lol.