can an old IMAC running OS 9.2 still access the internet with Internet Explorer 5.1

Yes.

(107923)

If by "access the internet," you mean web browsing as it's intended in 2014, the answer is NO. The final pre-OS X version of Internet Explorer was 5.1.7, released in 2001. That's 13 years ago, and the internet and web page design have evolved exponentially during that time. Some years ago when I was still using my older G3 Macs running OS 9.2.2, I started getting error messages from one web site after another, indicating that my browser (Internet Explorer 5.1.7) was no longer supported and to upgrade to a newer one. Those very capable (in other ways) Power Macs were retired from internet use. There are other browsers that you can try (search this Forum or the web for "OS 9 browsers"), but the bottom line is that any computer that boots from OS 9.x doesn't have the horsepower to provide full enjoyment of the internet. That's the primary reason that so many Mac and PC users replace their computers. The fundamental software still operates fine on older computers, but the video content that inundates web pages is just too much for an older computer to handle.

See my FAQ*:

http://www.macmaps.com/browser.html

For better alternative web browsers.