Welcome to SevenForums! I understand your problem. (<----- That sounds weird doesn't it?)
Ok so what you need to do is download EasyBCD from here: Download EasyBCD 1.7.2 - NeoSmart Technologies
And then install it. (I'm not gonna go through those steps because they're straightforward.)
When you've installed open up EasyBCD.You should see a page that has a options at the left and text to the right.
Go ahead and click "Add/Remove Entries".
Under where it says "Manage Existing Entries" It should only have Windows 7.
Where it says add an entry click the Windows Tab.
Next to type choose "NT/2k/XP/2k3"
Next to name just write in Microsoft Windows XP or whatever you prefer to call it.
Then choose the Drive that you have XP installed on and click "Add Entry".
You should have two options now.
Oh and by the way, It's true:
IMPORTANT: The RC will expire on June 1, 2010. Starting on March 1, 2010, your PC will begin shutting down every two hours. Windows will notify you two weeks before the bi-hourly shutdowns start. To avoid interruption, you'll need to rebuild your test machine using a valid version of Windows before the software expires. You'll need to rebuild your test PC to replace the OS and reinstall all your programs and data. (To learn more, see Frequently asked questions.)
Report your findings please