This is a duplicate of the ticket 684441.
Since this is a public forum post I will answer again so our other customers can benefit from this information.
1) Test Studio ONLY supports IE 64 bit on Win 8. You cannot execute tests in IE 64 bit on Win 7.
2) In general you could start any process you want with a single line of code:
"C:\\path to the IE exe"
However Test Studio cannot attach to IE 64 bits under Win 7 and cannot execute tests in it.
the Telerik team