My motherboard has a 20 pin power socket. While the new power supply I purchased has a 20+4 pin connector. So I assume that means it is a 24 pin connector. Can I just plug the 20+4 connector into the socket and keep the extra 4 slots on the right. Or do I need to purchase an adapter?

PSU - http://www.newegg.com/Product/Produ...

The 20+4 plug was designed to be used on either 20-pin or 24-pin boards...just unsnap the +4 & use the 20.

BTW, horrible PSU choice.

http://www.newegg.com/Product/Produ...

"BTW, horrible PSU choice."
Agreed.
If you use an el-cheapo PS like that, you are much more likely to have problems with it, it is a lot more likely to fail eventually, and when it does fail, it is a lot more likely to damage the mboard or anything connected to it.
If you do use such an el-cheapo PS, you should have some kind of software loaded and running all the time in Windows that is monitoring the voltages it produces so that you can be warned when some voltage has gone out of whack, but that may not be enough.

E.g. see this - the same software that monitors temps usually monitors voltages and fan rpms:
http://www.computing.net/hardware/w...

Yea I know the PSU sucks, I only had $300. And it all got spent on motherboard, ram, dvd drive, processor and graphics card. I figured my old PSU would work with the motherboard, but that PSU didn't have a 4pin connector for CPU power. And I had to scrap together money for buying the one above.

Do you want to put yourself at a lot greater risk of that cheap PS trashing your mboard, etc.?

"I figured my old PSU would work with the motherboard, but that PSU didn't have a 4pin connector for CPU power."

That's a minor prolem.
If the old PS has enough capacity you can get 20 to 24 pin wiring adapters for about $15 or less, or some mboards can use either 20 or 24 pin connectors from the PS despite there bieng a 24 position connector on the mboard - see your mboard manual.
If the new mboard does not have PCI-E slots, I've been told you never need more than 350 watts capacity, and you can probably make do with 300. If it has PCI-E slots, you need at least 430 watts capacity to allow for the support of the mboard and lesser PCI-E video cards, and 500 watts will handle just about any mboard and PCI-E video card combo.

Yea my old PSU was 230 watts though, so didn't even power up my motherboard.

If I were you, I would only use the cheap PSU until you can save up enough money to buy a better one (e.g., the one jam recommended). Replace the cheap one with a good one, and keep the cheap one as a "spare" (in case you need it for temporary use in the future again). I understand that funding may be tight, but a cheap PSU may go bad, and may cause damage to other components (as Tubesandwires points out). Don't be "penny-wise and pound-foolish"!

1 Corinthians 15:3-4