Windows Boot With Only 10gb Used Hdd

[OptikaliLLusion]

Alright, this has been bugging me for a bit... when I got my SATA hard drive, I didn't notice much of a difference. I figured since it is being "broken in". Now, days later, the XP boot takes forever. No spyware, adware, and I haven't downloaded anything that could contain something volatile. What gives? Is 17Mbps differece nothing w/o RAID? And if I were to RAID, would I, at boot, press Ctrl+F4 or what it is and RAID it? And would my data stay intact if I RAIDed, or not?