I hope I'm not out of bounds for asking this, but how old are you? Not that your age will have any negative effect o nyou or anything.
If you've already purchased all your parts and cannot return any of them, then yes, you are pretty screwed until you get more money.
1GB ddr isn't going to get you anywhere. You'll be lucky if you can even run Windows 7, or Vista. You'll have to settle for xp with just 1GB, and even then you'll be going slow as a boat upstream for the most part. You wont be able to play most, if any, games either
To run Windows 7 and play games effectively, you'll need at least 4GB or RAM. Win7 takes at least 2GB of RAM to run smoothly. The other 2GB would be used towards your game and other programs and such.
What RAM did you buy? The G.Skill 4GB (2x2GB) 240-pin 1600? If you bought that, then it may just be your mobo that is causing you to have problems. If it's your mobo, save up $80-$100 and you'll be able to buy a new mobo that can make full use of your RAM.
Save up another $100 and you can buy a one-time install OEM system builder version of Win7 Home Prem and be able to use that. If you ever need to reinstall it, call the Windows support team and they'll reset it for you if you tell them you need to reformat or some such.
Also, for future reference, do not discuss pirated content on forums such as Tom Hardware, it will only get you a warning, or maybe even banned.
If you can come up with more money and give a new budget, and maybe post some of the parts you already have (from a previous computer or from the computer parts you already bought) I may be able to help you out with building a (super) budget gaming PC.
You can play most games (may have to be on mid-settings) with just a duo-core and a couple of hundred in improvements, and that was 3-4 years ago, so it'll probably be better performance for the same price as back then. ....That is if you are upgrading an old computer.