The law says "purchase of a personal computer". Technically speaking, you didn't buy a personal computer. You bought parts to be assembled into a personal computer. If the IRB wants to be strict, they will enforce that interpretation.

However, I would say that if you can prove that all the parts your bought were used to assemble one computer, you probably could argue that it qualifies. But be prepared to fight because the IRB isn't known for being very open-minded.