32 bit is the default.
No, you cannot.
They are no longer manufactured.
As a whole, the Pentium 4 has a higher maximum performance than a Pentium III. The Pentium III performs the same as or better than Pentium 4 at the same clock speed, but the Pentium 4 has a higher max clock speed (which the Pentium 4 was designed for).
Series of processors / Generation of Pentium processors.
Intel Pentium processor
Both processors are in the Pentium Dual Core family. The Pentium Dual Core E2200 is better than the other.
The Pentium 166mhz is a old socket 7 a very early Pentium prossessor,The Pentium 4 is modern form factor,much faster and more prossessor cach than the old chips.
The Intel Pentium D, Core Duos (and Solos), Core 2 Duos (and Quads), Pentium Dual-Cores, and the Core i7.
That would require purchasing a new motherboard, processor, and power supply.
No. The Intel Core 2 Duo is much faster than the older Pentium 4.
Celeron doesn't refer to any particular processor series. Celerons were cost-reduced versions of their Pentium equivalents. The Celeron in question could be based on a Pentium 2, Pentium 3, Pentium 4, Pentium D, or Core 2 Duo. In which case the answers would be "Pentium 3, Usually Pentium 3, Celeron, Celeron, and Celeron", respectively.