Why are you still running VMware Fusion 3.0.1, you should have upgraded to the latest VMware Fusion 3.x which is VMware Fusion 3.1.3.

Unless things have changed with VMware Fusion 4, and I don't think they have, you can only have one version of VMware Fusion installed at a time however you can revert to a previous version if you don't like VMware Fusion 4 after trying the Fully Functional Free 30 day Trial.

Also you can/should backup the Virtual Machines before upgrading or at the minimum take a Snapshot so you have an easy avenue to revet to a known good working state if needing to revert back to a previous version of VMware Fusion.

Have a look at: Downgrading from Fusion 4 to Fusion3 (2005310)

3 and 4 can't coexist.

to trial this (applies to a non-BootCamp VM only):

a) back up your VM

b) make sure you have your Fusion 3 install disk (or image) around

c) uninstall Fusion 3 (but make sure you keep your VM files)

d) install Fusion 4 - make sure you use the "upgrade from 3" icon on the trial disk image

e) start the VM

If you don't like Fusion 4, there are several threads here talking about how to revert, and there's a kb article, too. Example:

           What is the proper procedure to downgrade from Fusion 4 to 3.1.3?      

I'm not sure how to do this with a BootCamp VM.

@Woody and @ShaddamIV Thanks for your anwers. You have both answered pretty much to the point. I am split on how to mark both as 'Answered' because the timestamp on the answer is same too . BTW I got my Fusion version wrong. I am running 3.1.3 not 3.0.1 sorry about that.

Currently I am marking both of you as Helpful Answer. I'll let Admin decide if one should be marked Correct Answer over the other.

Just for clarity I posted ahead of ShaddamIV as my post appears in the list first however the information presented by both of us answers the question so marking both as helpful is just fine and the thread itself is marked as answered so it will be helpful to others as they search and that's the next most important thing to answering your questions.  So all is good, not to worry and you cannot buy anything with the points so it's not a big deal.