It wont matter at all. Cause you will have to use a Windows 7 disk in order to get that partition activate again and then use EasyBCD to add the entry for XP and then Ubuntu. There is no step by step guide for everything you want to do cause very few people want to use a dead OS anymore. So you will have to use the Wiki to read about how to get XP working and then Ubuntu or vice versa and go through both guides. Then merge them to make 1 boot menu for all 3 OS's.