Don't know how to ask this, so I will give an example.

when you go to a site (newsforblondes.com) is an easy example. The control that comes up is most likely wmp 10 (right click on the control pane of the player and goto "about"
On the machine in ?, that control comes up as Media Player Classic 6.4 (and doesn't work of course)
How do you switch this back to WMP10?

WMP10 > Tools > Options > File Types > Click select All Button > OK

I didn't know you could have more than one version of medial player thou.
Let me know if that works.

I may have already tried that, I'll check again tomorrow. wmp10 is the default player for wmvs. I even uninstalled media player classic and ie still is getting it from somewhere. I couldn't find anything in the registry and it isn't listed in ie'* active-x controls.

nope

Ok
control panel>add remove programs>set program access and defaults
Try setting WMP as the media player

otherwise try unistalling or upgrading media player classic. Its actually not a MS product but seems to have a following.

nope, nope and nope. MPC does not install, you just run the file. I searched and deleted all references and instances of it from hd and registry. even did a ie7 reset which puts ie7 back to virgin. Going back to newsforblondes.com the active-x popup block came up and said it wanted to install windows media player control. agreed, and it still popped up to MPC.
So, I just got ahold of MP10setup.exe and reinstalled. Works now