You could possibly make the old case work ....... but, you will want to upgrade your power supply (psu) to 300w (or more) and with the newer faster processors available now, additional case cooling is also required.
The newer model cases and psu's are much better designed for cooling, and are upgraded to provide additional electrical connections and motherboard / heatsink mounting studs for Athlon & P4 cpu's.
It's usually more economical to purchase the psu, when it is included with a pc case ....... so you will probably be much better off ($$$, power and cooling wise) ........ to just go ahead and upgrade to a newer, better case/w psu to enclose your new system .......!
Last, but not least, Packard Bell cases are usually just ..... butt ugly ...... IMO! (no offense meant - if you like them)?