If you end up deciding to reinstalling Snow Leopard, you can use the last most “up to date” Mozilla Firefox ESR 45.9 for that version of the Mac OS. The last version is almost a year old, but, at least, it is much newer and more up to date than that very old version of Safari for OS X 10.6 Snow Leopard.
Firefox 45.9 ESR .dmg install file here.
Dbl click to download, locate the Firefox 45.9 ESR.dmg on your Mac.
Dbl click on the file and it should put up both a disk drive looking image and a pop up installation window.
Drag the Firefox Application icon into the Application folder shortcut icon in the same install window.
The go to your Applications folder, find Firefox, the launch it!
You may need to update Adobe Flash Player to the last compatible version for Firefox 45.9
You need to use Adobe's Flash Player uninstaller, first, to uninstall the older Adobe Flash Player.
On the Adobe Flash Player section of the Adobe website, you will need to look for the last Adobe Flash Player version compatible with Mozilla Firefox 45.9.
This is the Adobe Flash Player you are looking for on the Adobe web site.
Adobe Shockwave Flash version 18.104.22.168
Look toward the bottom half of this webpage link.
Once downloaded on your Mac, dbl-click to open the zIp file
Dbl click to Install the Mac OS version if there is one listed in the archive file (might be a .dmg file).
When you open that Adobe Flash Player archive file, it will create an archive folder.
Dbl click that folder, two other folders will appear.
Click the first folder WITHOUT THE words debug in it!
When that folder opens you are looking for a Mac OS .dmg file with this name
Dbl click on this and begin the install procedure from the brownish red Adobe install folder that appears.
On older, unsupported OS X versions, you CAN still access and get at your DropBox files from the DropBox website instead.
DropBox dropped support for their desktop widget for older OS X versions UP to OS X 10.8 Mountain Lion, which I still use fairly regularly use.
I access and get my files from accessing my account directly from the DropBox website, bookmarked on another uo to date third party web browser for OS X 10.8 Mountain Lion, in addition, to creating a shortcut to the website on my desktop. Not as convenient as DropBox’s menu widget, but it works.
Good Luck to You!