Wireless keyboard/mouse boot up problem


I installed W7 as dual boot option in separate partition on my PC. Other OS is XP.
the only way to use my mouse or keyboard now (wireless items) is to have a "USB thumb
drive" plugged in. I need to be able to use my keyboard during boot up to be able to select " select earlier versionOS" as I have a dual boot option XP/W7 an earlier post placed.
Any help please?:frowning: