BleepingComputer.com: Unable to upload files with any browser on any website

Hey guys, my problem is pretty much explained in the title of this thread. I've tried using IE, Firefox, Safari, and Chrome to upload my files to various sites. When I wish to upload a file and click on Browse... the window that usually appears and lets you choose a file to upload is just not there...

I've gone to control panel and looked at my internet options and nothing seems to be out of the ordinary there.. I've tried disabling the firewall and there is no difference at all. Just yesterday I downloaded a program called "Advance Windows Care" which repairs registry and supposed to optimise my computer and it did remove spywares etc but I'm still unable to upload my files.

This is quite frustrating. I hope someone here is able to help me with this particular problem.

Thanks!