Actually, I don't even do 3D animation. You can only do 2D animation with Flash Professional 8. I'm afraid in investing in a personally built computer because of compatibility problems and I am quite a newbie in hardware and such.
I found a computer on Dell which appears to be like the one you guys have specified.
Brief details of the computer:
Intel® CoreTM 2 Duo Processor E6300 (1.86GHz, 2MB Cache, 1066MHz FSB)
Genuine Windows VistaTM Home Premium
2048MB DDR2 RAM (Upgraded from 1024 MB)
19" Analogue Flat Panel Monitor
320GB (SATA) Stripe Raid 0 Hard Drive
16x DVD+/-RW Drive
256MB PCI-Express nVidia GeForce 7900GS
Integrated Gigabit Ethernet 10/100/1000