Yes there is a way for the programmes themselves, but not for your logon name as far as I know.
Go into Windows Explorer (right click on [Run] and then click on [explore]), this will take you to your start menu, if you right click on the relevant folder, it will come up with a series of options, one of which is [properties](the bottom one), click on this and a block comes up relating to the programme, the box by the side of [shortcut key] should be blank, you can enter any desired shortcut in here, either [ctrl] + [A] or so on, then click on [apply] at the bottom, now you can return to the main menu.
I''ve done the same with some of my programmes and they work ok.
I would like to set up some shotrcut keys to use for logging in to frequently used programs and web sites. This way I could use a keystroke such as "Ctrl L" to type my logon name, hit Tab and enter my passowrd. Some word processing programs have this feature. Does anyone know if Windows XP does?