As others have said, to paraphrase, it's not "them" it's "you." Or rather, your browser or a related setting.
Absolutely no harm in running more than one browser on your PC. I use IE, Firefox and Opera. If any website causes "issues" in one, I try it with one of the other browsers.
Whatever browser you're running, keep upto date. Lot of nasty people out there on the Internet trying to damage and steal via "old" browsers.
I did see some problems with Copplestone on one of my PCs with IE. Do seem to recall it was a Jave update that fixed. Months ago though and the memory dims...