Can I Upgrade to High Sierra?

My Safari won't work.

I keep getting the "This Mac can't connect to iCloud because of a problem with....." (my iCloud account), and it tells me to open iCloud preferences to fix the problem, but won't let me open iCloud.

I figure upgrading to High Sierra might do the trick?

What I'm working with:

• MacBook (13-inch, Late 2009)
• 2.26 GHz Intel Core 2 Duo
• 8 MB RAM
• 500 gb SATA hard drive

Someone told me I shouldn't do it unless I had a Solid State Drive?