Can this GPU work in this pc?

[DemizeGamer]

Can my EVGA GT 610 (One that can work in a small bracket computer) work in my Dell Optiplex 755 MT? I just got this pc today. If I need more than 309 watts, can I use my old one which is 400 watts? Here is a link: http://www.corsair.com/en-us/builder-series-cx400
Also can I use an extra 512mb X 2sticks of memory that I have? It is DDR2.

 

[DeathRabit]

GPU will work on standard Dell PSU.
You can try put extra ram, but difrent ram sticks can not work * in worse case scenario PS will refuse boot and you will need remove this 2x 512 to computer start work again, also this can give instability random PC reset ect, but most liekly will work