"I'm studying for the A+ , and bought the HP pavilion intel 600MHz Machine"
This is the Dell community forum.
Nothing Dell supported or related has been posted here.
The A+ certification is also not a Dell product.
Windows 95/98/ME/2000 are not part of that certification and have not been for over a decade.
Windows XP is End of life End of support as of April 9, 2014.