Are you a college or high school student?
If you are, you can get windows 7 or 8 for free (the Pro versions too).
Not sure if a P4 can take 8, I def think it can take 7 with lean performance.
You could get a decent Win 8 computer right now for 250-400 dollars.
I actually just bought this:
Amazon.com: ASUS 1015E-DS01 10.1-Inch Laptop (Black): Computers & Accessories
Its a sandy bridge celeron, but It does alot of basic things great. Plus the battery is perfect for me to take to school (My chromebook's only lasts 2 hours vs the 5-6 I expect with the new pc). RAM is not upgradeable, but if you run a lean W8, it will be fine.
Trust me, buying an expensive laptop or desktop when you dont need the power is a horrible idea. I had an IdeaPad Y460p that crapped out a week after the warentty expired... it was barely 1.5 years old. It had a graphics card issue... I just junked it today too :evil: