Ok, so the comp is HP Pavilion p7-1003w and this is the specs:
N-Alvorix-RS880-uATX (Alvorix)
AMD Athlon(tm) II X4 650 Processor 3.2 GHz
8.00 GB Memory
64-Bit Operating System
Integrated graphics using AMD ATI Radeon HD 4200
Integrated ALC888S-VD audio
Internal 250W (100-240V)
And the case is ATX
Height: 38.81 cm (15.28 inches)
Width: 17.50 cm (6.89 inches)
Length: 40.99 cm (16.14 inches)
So does integrated graphics mean that I have to get a new motherboard in order to install a new GPU?
Also thanks for the help Pecon, I am considering it.,