A few things:
First, the virtual images they reference and are talking about require sever 2008 hyper-V. So you can scratch the use of these images on your laptop. (unless you blow out your existing OS, and install hyper-V on it, and the windows + windows server 2008 on top of of hyper-v). Windows 8 will have some versions that come with hyper-v, but let's not go down that road as of yet.
Next up, is at noted, these server based systems need quite a bit of ram. To run a WHOLE SharePoint server is REALLY quite large of a system. This system has to SQL server, has to run the web server, and THEN has an amazing number of additional services that need to startup and run such as workflows, Excel services, Access Services, indexing services and several web servers such as the admin site. – and this is the short list!
You need a min of 4 gigs of ram to just setup + install + setup SharePoint 2010. In fact, the min requirement is stated as 8 gig, but it will run quite nice in 4 gigs for testing.
Next up, as noted you cannot use the free edition of Virtual PC on your laptop to run such a virtual system such as 2008 r2 since VPC ONLY supports x32 bit operating systems as guests and you need a x64 bit VM here to run server 2008 of which then SharePoint runs on top of.
Assuming you bump your laptop up to 8 gigs, then you can most certainly grab something free like Oracle/Suns Virtual box and it does support x64 systems. And this setup will then run SharePoint 2010, but you cannot use those supplied images since they are not compatible with v-box (Not looked, but v-box does have support for VHD images from VPC, and they often also have additional images.
There might be some conversion utility, but that's another question.
So, unless you have 8 gigs, and unless you running hyper-V (server 2008) as your host system, then you cannot use such a VM setup on your laptop.
With more ram, you would have to install + setup hyper-V on your laptop.
With your current setup, you could consider to install + setup SharePoint on your laptop, but such a massive install would forever cause so many changes to your laptop that I would not being to consider such a setup on a dev box anyway. And again, you cannot use those VM images for such a setup + install on your laptop if you choose to NOT use VM technology as is being suggested with this idea.
And to be fair, you would never un-tangle the mess of systems that such a large server system with a GAZILLION services etc. that is installed anyway. In other words, I would build a box from the computer graveyard and use that!
So these VM's are not setup for your laptop environment you have. A longer shot would be if you had 8 gigs, and the disk vm images could be used with something like v-box (since it supports x64 VM's and you need this ability).
You need more hardware here regardless, and using the above images suggests that you have to install hyper-v on your laptop.