kickstar, The major problem I see is the video subsystem. The NVIDIA GeForce Go 6100 does not have any dedicated memory. Hoster's minimum requirements. Quoted from the Hoster page:
Graphics Video card with at least 32MB of RAM. that supports Direct-X 9.0b or higher
(cards with less than 32MB RAM usually don't support 9.0b). Dual-display requires an ATI Radeon 9000 or higher, or NVidia equivalent. S3 video cards or chips in laptop computers don't support Direct-X 9.0.
While your card will support direct-x 9, it is starving for memory. Is this a dedicated machine, or do you use it for other things? If it is a dedicated machine, you can go here
http://www.blackviper.com/ and use the info to tweak your system to get rid of any overhead. This
may allow you to run 4.06 on your older laptop. I have had good success in the past using these methods.
Unless you are very comfortable making these changes (I am), I would wait untill you have Hoster installed on your newer machine before you make these changes. You seem to have been able to avert disaster by using system restore. You could always do it again.
As far as the Vista machine
click here to visit the page that tells you what the required changes are to Vista. Then, if you still can't install 3.321, submit a support ticket to see about clearing up your reg code for a second install.
http://www.mtu.com/support/support-frame.htm
I hope this helps you in some way. Please post back here with your progress. It may help someone in the future.