The full browser requirements can be found at: http://www.washington.edu/user/hr_payroll/technology/opus.html
However, if you are having trouble with OPUS, the following settings are the most likely culprits. Here is how to check these settings on your own Internet Explorer (IE) browser, version 5.
Step 1: Choose Tools->Internet Options
Step 2 : On the General tab, find the Temporary Internet Files area and choose Settings
Step 3 : Select the Every visit to the page radio button and click OK
Step 4 : Select the Security tab, click on Local intranet and choose Custom Level
Step 5 : Scroll down to the Cookies section and set Enable for (1) Allow cookies that are stored on your computer, and (2) Allow per-session cookies (not stored)
Step 6 : Scroll down further to the Miscellaneous section and set Enable for both (1) Display mixed content and (2) Launching programs and files in an IFRAME
Step 7 : Scroll down to the Scripting section and set Enable for (1) Active scripting, and (2) Scripting of Java applets and click OK
Step 8 : Set Enable for Display mixed content, as described in Step 6 for both Internet and Trusted Sites and click OK
Step 9 : Click OK again to save all your changes! (It does not matter which tab is selected at this point.)