Hi see the answers in bold.

>Hi,
>
>Q1. Can i install VFP 6 and 7 into same machine ?
Yes
>Q2. What is diff. or new function at ver.7 ?
Read http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fox7help/html/neconlanguageenhancements.asp
>Q3. Is't ver.7 more for Web-database fuction ?
I don't quite understand what you mean VFP7 is better for web development than VFP6
>Q4. VFP7 can work fine in old machine ? ( PII CPU / 64M RAM )
VFP7 can be installed in win98 or above with the above configuration the developing environment will be slow.
>Thanks a lot