What should i upgrade my motherboard to

One thing I wish you to know right off of the bat;

When Windows is installed on a computer, it assigns hash values to certain major hardware components;
1) Processor
2) Motherboard chipset
3) Harddrive
4) BIOS program, version, and date
5) Graphics chipset

Change any two of these components, and Windows will 'think' it is being stolen.
'Thinks' the Windows program that has been installed on that computer, is being removed, and installed on another computer.

Microsoft User's License states, "One GENUINE copy of Windows per ONE computer"

[Microsoft makes a Master disk of a Windows operating system. From it all GENUINE copies are made, and sold to the consumer]

IF, you are LUCKY, the Windows activation screen will come up.
IF not, (Which is MOST of the time), you need the Restoration Disk, or a new GENUINE copy of Windows.

You are upgrading the motherboard. (GOOD for you! You rock!)
You will be changing at least the motherboard chipset, and BIOS program. (And version, and date)

Just wanted you to be aware.

Got all your ducks in a row, don't need the above info?
Let's continue;

I know you do not need this info, but IMHO you are wasting money, in buying a MicroATX form factor motherboard.
(Yes, I know it is what is required to fit that computer case)

Why?

Because of the limited space inside the computer case.
MicroATX form factor motherboard, is usually installed in a MicroATX form factor computer case.
Such is the case with the Pavilion a6645f Verde Desktop PC,

1) http://www.geeks.com/largePic_all.asp?invtid=FQ424AA-PB-R&pic=FQ424AA-PB-R-soft.jpg

2) Motherboard Specifications,

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01357135&tmp_task=prodinfoCategory&cc=us&dlc=en&lang=en&lc=en&product=3820313#N50

The photo of the motherboard is upside down, in relation to how it sits in the computer case.

See how the 4-pin ATX +12 Volt power cable is in the way?

http://www.playtool.com/pages/psuconnectors/connectors.html#atx12v4

See the Electrolytic Capacitors on the left side?
(Right side when installed in the computer case)

Radial Aluminum Electrolytic Capacitors,

http://www.panasonic.com/industrial/electronic-components/capacitive-products/leaded-electrolytic.aspx

See the audio ports square metal body to the left, above the Electrolytic Capacitors? (Orange and Blue ports)

Limits;

1) The size of the graphics card. General consensus is the longer the graphics card, the more graphics 'power' the card has.
Sounds dumb I know, but look at the average length of high power PCI Express graphics card, that pack a graphics 'wallop'
(10 -1/2 inches, and longer)

Also the thickness of the graphics card.

2) Micro-ATX computer case cuts down needed air flow, to the cooling components inside the computer case.

I know you are stating you are going to change, and upgrade the motherboard, but generally all of the MicroATX motherboards, follow the basic setup of that Asus M2N68-LA motherboard.

If I were going to spring for a better motherboard, and graphics card, I would also spring for an economical full size computer case too.

One example,

http://www.directron.com/cs888uvbl.html

Not what I asked for joecoolvette.
I understand. Thank you for letting me post a constructive argument.

To go on;

The Asus M2N68-LA motherboard has an AM2+ processor socket.
Supports AMD processors that use an AM2+ processor socket.

It also supports DDR2 Sdram ram memory that operates at 667MegaHertz, or 800MHz.
(PC2-5300 and PC2-6400, respectively)

If you are going to replace the motherboard, you probably want to use the same Processor, and Ram Memory. ('Natch)

A) http://www.ebay.com/itm/Biostar-TA785GE-AM2-AM2-AM3-AMD-TA785GE-128M-Motherboard-/140808779966?pt=Motherboards&hash=item20c8db78be

NOT an advertisement for website, nor seller.

Solid Polymer capacitors used for the processor motherboard voltage regulator circuit. (Which is part of the motherboard voltage regulator circuit)

Supports AM2, AM2+, and AM3, AMD processors.
Supports DDR2 Sdram at 667MHz, or 800MHz.
Supports SATA harddrives
Supports IDE (PATA) or SATA optical drives

Do I think it will just drop right in? When you are referring to a pre-built computer manufacturer case, and an after market motherboard? Maybe yes, maybe no.

It does come with it's own I/O shield.
(Input/Output area on the back of the computer, is where the Mouse, Keyboard, audio ports, etc., is mounted.
The I/O shield is the thin metal plate that surrounds them)

Will it fit? Maybe.
Will the expansion slots on the motherboard, (2 - PCI, 1 PCI-Express x16), line up with the expansion slots in the computer case? Maybe.

Just one example. There are more around.
(Buying from Ebay.
Just stating some examples in case Ebay is one of your choices.
This seller indicates will not ship to outside the USA.
No returns or exchanges.
29 sales. 100 percent feedback.
If it were me I would look for a motherboard with Buy It Now, and a good return policy. Just saying )

It is tough to find a decent motherboard, that has a processor socket that will support an AM2+ processor, the correct processor Front Side Bus, (FSB), and 667 or 800MHz DDR2 ram memory, AND is a MicroATX form factor.

Everything is going to DDR3 Sdram, and is usually an ATX form factor motherboard.

For additional questions please post in a Comment.
Regards,
joecoolvette