Hello all. I have a Dimension C521 (slim case) and I would like to upgrade my CPU from an AMD Sempron(tm) Processor 3400+, ~1.8GHz to an AMD Athlon 64 X2 6000 3.0GHz 2MB socket AM2 89W ADA6000IAA6CZ. But I'm uncertain about a few things, which is why I am here. I would like to know:

• if the AMD Athlon 64 x2 6000 will work with my computer
• what the recommended BIOS is
• if the fan the C521 comes with is good enough to keep it cool
  
• if a 280W 955.39BTU/hr Maximum PSU is fine
• if you have any questions =D

Here is the owners manual, if it'll help - ftp://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_dimension_desktops/dimension-c521_owner's%20manual_en-us.pdf

Also, if I were to upgrade my GPU, what would you recommend?