In my win98/2k dual boot, i have the program files shared. I install the proggie in win98, reboot to 2k and install the program in the same directory. Almost every app is shared > office, ie6, getright, winzip/rar/ace, cdrwin, clonecd, quicktime, mediaplayer, etc. the only app not shared is Norton sys works 2001, but it may be possible with the 2002 version.
As to using a common start menu, it is possible. You will need to use a registry editor to change the location of the start menu. TweakUI should have this functionality, so give it a try first. However, PROGGIES MUST BE INSTALLED ON BOTH OS\'s FOR CORRECT OPERATION. Installing a proggie such as office in 98 and rebooting to 2000 (where it is not installed) and then running it from the common start menu will result in errors. Programs use registry entries to save alot of configuration data, hence the need to install on both OS\'s.
To disable the windows 2000 bootmenu, edit the boot.ini file and set the timeout to zero, or go to control panel>advanced>startup and recovery>settings>system startup> and uncheck \"time to display list of operating systems\"
However, I do not recommend doing this. Instead, set it to a low value eg 3 seconds, so that gettign into safe mode, etc is easier.