I currently have Vista on my computer. Which I would like to get rid of.

1) I have read that Windows 7 be loaded over Vista. Would this be an improvement or just provide me with a different set of problems?

2) Can Vista be completely removed during the process or do they have to run in parallel?

3) Will Vista versions of programs run in Windows 7?

The Windows 7 Release candidate is available (a beta-version that will eventually become inactive). I would not recommend installing this over Vista at this time. The final release is supposed to be later this year:

Welcome to Windows 7 (http://www.microsoft.com/windows/windows-7/)

1. probably an improvement.
2. you can never remove everything unless you do a clean install.
3. probably.

Windows 7 requires more from the hardware. If you have a Vista-compatible machine, I suspect you won't have any problems (except possibly driver problems, but hopefully most of them will be solved when the final release comes out).