What kind of graphics card will work for my desktop?

I have an old Compaq desktop that still runs pretty nice. I tried to run the minecraft demo on it but it showed an error message saying that it could run it. I know it needs a new graphics card and I know that I gotta use one that works with the wattage of my computer. Here are some specs:
Desktop: Compaq presario SR2020NX
AMD athlon 64 processor 2.2 GHz
4gb ram
graphics card: Nvidia GeForce 6150 LE

Minecraft adventure map ideas?

I'm making a Minecraft adventure map, and i need some ideas. Can you give me some good ones?

Note: I'm in minecraft 1.4.7. So I'm missing a lot of stuff(hoppers, minecart with hopper, minecart with TNT, daylight sensor, weighted pressure plates, droppers, etc.)

Can't log back into minecraft?

I haven't played MC in a while I got back on and, I have gotten it to update 1.6.2 but it says I need to log in again and that I'm in demo mode but I bought minecraft I don't get it.

Why can't i play minecraft offline?

My girlfriend downloaded it when she still had internet lost her internet but plays it still when ever she wants without internet I downloaded it and can't play unless I have internet

Trouble downloading minecraft?

I open minecraft and click play.

this is what it says

Gave up trying to download https://s3.amazonaws.com/....Final.jar for job 'Version & Libraries'
Finished downloading C:\Users\home\minecraft\versions\1.7.4\1… For job 'Version & Libraries': Downloaded successfully and etag matched
Job 'Version & Libraries' finished with 26 failure(s)!

any help?

What PC for gaming should I get?

I live in Ireland. I'm looking for a cheap but good PC for gaming (as most people) . I would require it to run games like BF4, Crisis, CoD, Minecraft etc…
I would see my price range being 500-700 euro maybe a bit higher.
I'm looking for something with quite some space and a good processor along with a solid graphics card, something that would not lag if I started running BF4 and recorded it with Camtasia Studio, because that's what I want, a good gaming PC to record gameplays to YouTube.

Which of these computers is a better deal?

I will be using the computers for internet, like youtube etc. Also some 3D games like minecraft, Civ V, TF2)

ps: i know i'm a noob for not building my own computer

#1: http://www.futureshop.ca/en-CA/product/asus-asus-desktop-pc-intel-i7-4770s-1tb-hdd-6gb-ram-windows-8-m11ad-ca002s/10268370.aspx?path=d5124af763fc930f362618de8ab3ba5cen02

#2

AMD Quad Core $699
or
INTEL Quad Core i5 $799

Both Systems Feature:
16 GB RAM
Windows 7 HOME Premium or Windows 8
2 TB (2000 GB)7200-RPM Hard Drive
20X Dual Layer DVD Burner
Integrated Video/PCI-E 16X Slot
Tower Case w/ATX Power Supply
HD Integrated Sound Controller
10/100 High Speed Ethernet
1 Year Parts/5 Years Labour Warranty

And will the games I've mentioned above lag on any of these machines?

Minecraft online singleplayer sucks?

How do I turn off online singleplayer? This is ridiculously bad. Haven't played the game in a long time, and I want to go back to the days where I didn't have to destroy a god damn block four ******* times before it finally breaks. I'm furious right now. HELPME.

Added (1). I want to play the most recent updates in survival, but I can't without getting enraged by the game.