If your company is forcing you only to use Internet Explorer 9 (which is unfortunate) I recommend that you follow all of our advice that we already listed above that does not involve using another browser or upgrading Internet Explorer or that goes against your company's policies (skip the parts that your company will not allow you to try (ask them if your are not sure) and follow the rest of our advice exactly, and if it still does not work after that let us know):
WordPress.com Browser Issues Support Page:
2. If you are using an IE browser in compatibility mode please disable that mode. http://www.sevenforums.com/tutorials/1196-internet-explorer-compatibility-view-turn-off.html
3. If you are running one of the browsers and versions listed at http://browsehappy.com/
(a) Try clearing your browser’s cache http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=32050
(c) Disable all browser extensions or add-ons temporarily.
(d) Try enabling HTTPS: http://en.support.wordpress.com/https/
Add both *.wordpress.com and *.wp.com to your list of trusted sites under the Security tab. Make sure to uncheck the box for “Require server verification (https:) for all sites in this zone.” http://en.support.wordpress.com/https/#frequently-asked-questions
4. You can use this link to see if your flash is up to date. http://www.adobe.com/software/flash/about/ If it’s not then go to http://www.adobe.com/products/flashplayer/ and download and install the latest version of flash.
6. If you are not successful let us know:
(a) Exactly what kind of device you are using to connect to the internet and to WordPress.com.
(b) Exactly which browser (and version of it) you’re using by checking here if necessary http://www.whatbrowser.org/
(c) Exactly what you experience including what any error reports you receive state.
My optional extra suggestions (if your company allows it, check with them first, because they probably will not allow some or most of them):
You probably should also make sure that Windows is up-to-date by checking for updates through Windows Update/et cetera (http://www.update.microsoft.com), make sure that your graphics/video card drivers are up-to-date and/or installed (Windows Update usually shows available drivers when there are updates, depending on your hardware), make sure that your monitor/screen resolution/size is set large enough, and/or make sure that your browser is maximized so that you can see more of the page.
Maybe even do a malware scan with whichever anti-malware program/software you use just in case to make sure that your computer is not infected with malware that could be causing problems, if you have no anti-malware program/software installed you can use Microsoft Security Essentials (http://www.microsoft.com/security/pc-security/microsoft-security-essentials.aspx) which is free and has both real-time and on-demand protection.
WordPress.com Advanced Browser Issues Page (Probably too advanced, you can probably skip this, unless someone from the WordPress Team asks for it or something like that):
I never use the Visibility Button and so I did not realize that it was gone until you mentioned it, but when I click on the Widgets in the list of Available Widgets there are some hidden Options there that probably used to be under the separate Visibility Button, please check those hidden Options and let me know if those are the options that you are looking for.
Do you have any extra suggestions for them that we missed?
Thank you for the help.
Good luck everyone,