Is there a definite way to absolutely check sites for cross browser compatibility?

Do I have to buy up some old computers with older versions of IE?

What gives! I'm so sick of checking and double checking compatibility issues...

There are several ways, actually, some free, some not.
There's a sticky at the top of the HTML forum for a compatibility checker.

Ahhh! Thank You Lady

OMG!, I just found a website that serves up old versions of browsers!

You can download stand alone versions that don't conflict with your current settings and cross browser check in just about any version of IE, Netscape, Firefox...

I download IE7, IE5 ... they all work!

Is this for real?

Yes, Evolt has been around for quite some time and everything is legit !