Download the three files you need on a different computer and transfer them to that computer.
Here's exhaustive instructions I recently posted for this process in a Windows 7 x64 case:
The web page you are visiting is...
http://www.microsoft.com/windows/virtual-pc/download.aspx
... you have (using Internet Explorer) chosen: "Ultimate 64-bit" in the first drop-down and "English" in the second drop-down.
You then get three links to click on.
"Windows XP Mode" (first)
"Windows Virtual PC" (second)
"Windows XP Mode update" (third)
You click on the first one. Continue for the validation, you allow the file to download and select to RUN the file. Watch for any yellow bars and allow things to download/run. It should eventually run and tell you:
"Windows validation was successful
Now you can take advantage of all the value genuine Windows provides, including extras like Windows XP Mode and Microsoft Security Essentials! Press the Continue button below to proceed to your download."
And you click Continue. Then you choose to *SAVE* the 469MB file "WindowsXPmode_en-us.exe" someplace where you can locate it and run it later. In your case - not knowing your Internet connectivity - I would suggest letting
it finish before doing the next step... Click on the second button and *SAVE* the "Windows6.1-KB958559-x64.msu" to the same location. Still not knowing your internet connectivity information - I would again wait until that download finishes before continuing...
Click on the third button and *SAVE* the "Windows6.1-KB977206-x64.msu" to the same location.
Now you have the three files, this is what you do.
Close everything. Reboot. Log in as an administrative user.
Go to the saved file location and right-click on the first file ("WindowsXPmode_en-us.exe") and choose "Run as Administrator". If it requests the administrator's password/permission - give it, it may/may not depending on
your setup (may take a few seconds to get to that.) Click "Next", Click "Next", Wait while it copies/extracts the virtual hard disk 'image', click "Finish".
Go to the saved file location and double-click on the second file ("Windows6.1-KB958559-x64.msu"). You *do* want to install the update ("Yes") and you should "Accept" the agreement. This may take a little time. Restart
when it asks.
Log in as an administrative user.
Go to the saved file location and double-click on the third file ("Windows6.1-KB977206-x64.msu"). You *do* want to install the update ("Yes") and you should "Accept" the agreement. This may take a little time. Restart when
it asks.
Test it out.