Transition from peasantry..help<3

Hi:)

Currently, I am in the process of transitioning from console peasantry. I own a very low end HP laptop with specs just barely good enough to run Half-Life 2 on low. Not to mention the CPU has a major overheating problem. My interest in PC gaming has metastasized astronomically since I began getting my feet wet within the Steam community...my friends from WoW...etc. Therefore, It is time for an upgrade.

I own a Dell Dimension 4700 pre-built desktop from years ago that is also crappy, slow, and near dead. It runs XP, albeit extremely slowly (Im not sure as to which part(s) causes this). It is micro ATX case. My plan would be to upgrade the motherboard, CPU, and ram for right now (major budget) in order to tide me over until i can save up good money for a brand new high end custom setup.

The parts im considering:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813128578

http://www.newegg.com/Product/Product.aspx?Item=N82E16819113282

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231303

im keeping a 300 watt PSU and the HDD from my old computer

What I need help with:

Would I bottleneck my new parts with the likes of an old hard drive? As far as I know, the hard drive works perfectly fine. Also, would XP be fine to keep with these new parts?...buying a new OS is a stretch at the moment.

Would these parts be good choices for running games like WoW, Garrys Mod, Portal 2, Dayz, Wildstar.. seamlessly smooth (Low graphics settings is fine)?

Are there any tweaks I can make to the parts I want to buy that would benefit me more?

Thanks in advance for any and all help, I hope i provided enough information:)

EDIT: My budget isnt really a set number, Id just like advice and direction on the lowest cost setup I can build to game in low settings seamless and smooth.

What's your budget?

 

Budget?  And yeah, your computer is pretty slow in terms of today's computers.

The dual core CPU might not be good enough for your purposes.  Higher clocked RAM will also help.

Check if your hard drive is SATA or IDE.  Google the terms if you want to see what the connectors look like.  If it's SATA, it should be fine.  Most computers within the past 4-5 years should be SATA.

I also know that Dell sometimes uses some proprietary connections, so you may want to watch out for that.

http://reviews.cnet.com/desktops/dell-dimension-4700-pentium/4507-3118_7-30981395.html

This is the specs for my desktop (that I dont play on) that id be upgrading with. As far as budget, ill update my OP but I dont really have much knowledge in this low end area...especially APU..so Id just say as low gaming smoothly.