Apple iPad 2 requires Windows XP with Service Pack 3 (SP3), or an upgrade to Windows 7:
XP SP3 update is available for free, more information here:
Make sure you backup ALL your data files and LR catalog files, etc. The only problem I encountered with SP3 update was loss of my ATI graphics card TV tuner. Apparently SP3 loads newer versions of graphics drivers, which may not be compatible with all cards. Unfortunately there is no way to "test" if your desktop/laptop will be affected, and MS does not provide the option to only install certain components (i.e. Apple iPad 2 compatibility update). In my case, reinstallation of the original ATI CD graphics drivers fixed the TV tuner problem.
My best suggestion is to first check the manufacturer's support website for XP SP3 issues relating to your specific model desktop or laptop. The XP SP3 update is required by many new devices and software applications. If you intend to keep your current system and stay on XP, then it makes no sense to put off this major update. Upgrade to Windows 7 is an option, but many older systems have non-compatible hardware and software on them. You can run the Windows 7 Upgrade Advisor to check compatibility here: