It might work, it might not.
Just bring all assets over to the new machine and open the project.
If Jim's suggestion doesn't work you can try exporting an
AAF, OMF or fcp XML from CS5.5 and importing into CS5.
But, you will likely lose references to some effects, etc using this method.
I have done some testing and I am happy to report that it is indeed possible.
CS5.0 will ask you to rename the CS5.5 project and then proceed to create a new project leaving the original one intact.
This is standard practice for Premiere when importing projects created in earlier versions of the software.