I'm digging around trying to confirm that CUDA will run on an M4400 or E6500 or other notebooks.

I found http://search.ap.dell.com/results.aspx?c=au&l=en&s=gen&cat=sup&k=cuda&rpp=12&p=1&subcat=dyd&rf=all&nk=f&ira=False&~srd=False&ipsys=False&advsrch=False ... being a list with seven entries.  The last four seem to provide new drivers that may work, with different OS.

I'd be pleased to hear if they help.

Here is the latest laptop driver (Vista 185.85)on Nvidias' site.It should work with all Dell laptops.

http://www.nvidia.com/object/geforce_notebook_winvista_185.85_whql.html

If you have winxp go here:

http://www.nvidia.com/object/geforce_notebook_winxp_185.85_whql.html