AMD Phenom™ II X4 Processor
AMD Phenom™ II X3 Processor
AMD Phenom™ II X2 Processor
AMD Athlon™ II X4 Processor
AMD Athlon™ II X3 Processor
AMD Athlon™ II X2 Processor
AMD Sempron™ Processor
Maximum CPU TDP (Thermal Design Power) : 95Watt
So, well, you have 2 options:
1. Keep the motherboard and the CPU. Get some cheaper GPU like HD7750 and a new PSU (of good quality, but not too expensive, like Corsair CX430- you don't need anything stronger). That is because the CPU is not really fast and there will be bottlenecking. I think it will be fine for online games and such.
2. Keep only the case and the ram (the one you have is great). And the storage - I presume you have it (HDDs).
Is it really not advisable to build a pc on an A10 processor?
Well, it isn't a bad option, but it isn't a good one either. A10 CPUs are more intended for notebooks, and are still easily beaten by CPU + discrete GPU options.
Like, by cheap Intel Pentiums G620 + HD7750- this combo offers *much* better framerate than A10 alone. Not to mention, i3 + HD7850.
Of course, a10 could serve you, but the thing is you would have to buy a new motherboard for it, since it doesn't fit the one you have. It doesn't make financial sense to me. If you want to save money go with i3 and some cheaper GPU like hd7770 insted of HD7850. Though hd7850 1gb is the world's best "bang for the buck" at the moment.