Windows 7 A strange problem with the taskbar, cannot switch between different instances of a single program

[stirfriedsushi]

I am having a strange problem with my taskbar. For some reason, whenever I have multiple instances of a program open, like firefox or word, I can usually mouse over the icon and switch between the different instances. But for some reason now I can't. I have been experiencing other odd problems like me not being able to click onto a firefox page on my second monitor when my first one has a flash or blip.tv movie playing on it at full screen.

Only recent change I have done was trying to install grandia 2 for pc. Otherwise no recent changes. I am planning on formatting soon so this isn't a huge issue, but I won't be able to do it for a few weeks and this is still annoying.

any suggestions?

thanks!