Off hand I would suggest two things in an attempt to resolve the connection speed issue:
1.) Upgrade all drivers, including those for your NIC, router, etc. This can have a drastic affect on the overall speed.
2.) Try disabling IPv6, the latest standard implemented under Vista, using these instructions. It may or may not have an effect, but some have reported substantial changes if they were connecting primarily to networks that did not support IPv6.
As to the hard drive space, check in C:\ or whatever you have your local drive set as, for a folder titled WINDOWS.OLD. When installing Vista, it automatically copies all of your old Windows XP system files there. Unless you have a specific use for them, though, you can delete the entire folder to free the space.
Finally, there is no way to 'downgrade' from Vista to XP, meaning you would have to wipe the partition and install XP from scratch, reinstalling all programs and restoring your personal files from backup.
Hope this helps,
Just recently I have upgraded my computer to Windows Vista Home Premium, and I must say that this is quite the impressive OS. I had no qualms with the operating system while using it, however I noticed that my DSL internet connection seems to have degraded after the upgrade and the space on my harddrive has waned from 208 gigs (this is before upgrading from Windows XP Media Centre Edition, my harddrive is 228 gig total) to 190 gigs.
The slowing of my internet connection is most evident when I play online games, and I have noticed that my ping, which was a normal 21-35, skyrocketed to 146-170. In every server I have logged in to, I was constantly lagging and this has never happened to me before on Windows XP Media Centre Edition. Is their anyway I can fix this, or this is a problem that will be smoothed out through Microsoft?
The harddrive space isn't necessarily a problem that's affecting the performance of my machine, but it is lost space that I could have really used for all my documents. With the constant music ripping, photography, gaming, and writing that I do I feel a little bothered that my harddrive's past capacity declined by 18 gigs. Overall, I feel that I can go back to XP without any impulses toward upgrading to Vista again. With that being said I was wondering how I could go back to using XP?