Here's the solution to the SnagIT sluggishness (hangs for several minutes)
I would try first turning off the magnifier window under tools > program preferences > program options. Uncheck the box to show magnifier windows. Click apply > ok and then try the capture again.
Check your security software and make sure that Snagit is set as a safe application. A security program that consistently scans the process will cause a very slow response like you are seeing.
Please also check your printers per this article:
Answer Title: Slow SnagIt startup
Answer Link: http://techsmith.custhelp.com/cgi-bin/techsmith.cfg/php/enduser/std_adp.php?p_faqid=742
Finally, please review the steps here and try these as well:
Answer Title: SnagIt crashes or hangs when launched
Answer Link: http://techsmith.custhelp.com/cgi-bin/techsmith.cfg/php/enduser/std_adp.php?p_faqid=137
Let me know what happens.