I.E. 7 and FIREFOX COMPATIBILITY

Hi

My company is consolidating it's IT dept. and as such it has put together
all of the employee's info along with access to most of the other company info.
On this note they are now requesting that for the remote user's they will have to have both I.E.7 & WINDOWS XP. I have been running VISTA and FIREFOX
with greta success. Can I install I.E.7 and still keep my FIREFOX , or am I
stuck with having to give in an change all of my O.S.. Along with tyhese change's I will have to drop my browser pop up protection, install active x links
and soften my browser trusted site's.

Thank you so much for any help,
BO