Windows 98 changed the behavior of the menu's under the Start Menu. In
Windows 98, when a menu is to tall to fit on your screen, you will see a
scroll arrow at the bottom, allowing you to scroll further down. In Windows
95, a second menu would appear next to the first, where the entries who would
otherwise not fit on your screen would be displayed.
To restore the Windows 95 like behavior:
1. Start the Registry Editor
2. Go to HKEY_LOCAL_MACHINE \ Software \ Microsoft \ Windows \
CurrentVersion \ explorer \ Advanced
3. Right-click an open area in the right pane and select New > String
Value
4. Name it StartMenuScrollPrograms
5. Double-click this entry and add the value false
6. Exit the registry editor 
To restore Windows 98 behavior, simply rename the value of
StartMenuScrollPrograms from false to true.
You can also use my Tweaking Toolbox for Windows, one of it's
functions is to allow you to change between a Cascading and
Scrolling Start menu.
For more information & free trial, check the Tweaking Toolbox for Windows
pages. 
You can also add Windows 2000 like functionality to the Windows Explorer
View > Folder Options > View tab. With the registration settings below,
you will create a check box called Multi-Column Start Menu, which will
let you change between the two styles "on the fly". This is a big advantage if
multiple users are using the same computer, and the users prefer different
styles of the Start Menu.
To add this functionality you will need to add a bunch of registry
settings. We have made a reg file for you, W2K-Start-Menu.reg, which
you can download from our FTP Site. Once you downloaded it, just double click
on it, and answer Yes when asked if you want to add the information to
the registry. You can also right-click the file and select Edit,
to check it's contents. This is how it should look:
REGEDIT4
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\explorer~
\Advanced\Folder\StartMenuScrollPrograms]
"Type"="checkbox"
"Text"="Multi-Column Start Menu"
"HKeyRoot"=dword:80000001
"RegPath"="Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced"
"ValueName"="StartMenuScrollPrograms"
"CheckedValue"=dword:00000000
"UncheckedValue"=dword:00000001
"DefaultValue"=dword:00000000
"HelpID"="update.hlp"
Note: the ~ break after \explorer is artificial. This
will be on 1 line.
