Hey guys John here,

I was wondering what gaming PC I should get for my birthday in March? I was thinking of either the Alienware x51 Extreme or the ASUS G20AJ-B09? I know you can build a gaming PC, but I don't know how to build a Gaming PC and being autistic, I might find that building a gaming PC might be too difficult. For LCD Monitors, I have interest in the Dell Ultrasharp 29 Ultrawide monitor or the ASUS 23" Widescreen LCD Monitor. 

Any thoughts from you guys?

I personally wouldn't get either cause you can get such a better deal if you pick the parts yourself. Have you considered just getting the parts and paying a person like $50-$80 to install it for you? Cause if you buy a PC from ncix.com, for extra $50, they will build the PC + test it + give you 1 year warranty on top of that and it should be much better performance for the exact same price than either of those two

Many sites have the option to assmble the pc for you. Research and select all the part and then pay extra $50 dollars. I know ncix does and am sure some others too. Much better way to go imo. 

Edit: Beaten ^^

Personally, I am more in favor of building it piece by piece but since you don't want to do that, I am basically useless here. However, I noticed you haven't mentioned how much you're willing to spend on it, which I think would be really helpful information for the people that can help you with this matter.
Only thing I can say is that Asus is a good brand overall, so I'd say you should lean towards it rather than towards Alienware (which are usually considered overpriced independently if it's good or not)

Asus make some really nice low latency gaming monitors. Personally I would stay clear of the Alienware stuff as you really are paying extra for the name, though they are good quality they come at a premium price. Asus are a good brand too so you won't go wrong with either.

As others have said though most computer stores online and even physical shops will usually give you a cheap option to have it assembled for you from the parts you selected, if you are willing to do the research and like to end up with quality rig and save some money that is the way to go.

Thanks for your input guys.

One you built yourself.

Theres a billion guides on sites and youtube to guide yoi every step of the way. 

Youtube isn't enough. I need a lot more than Youtube to help me.

It really isn't that difficult. 

btw can't I don't know newegg or whatever build you a PC if you buy all components there?

Given that the rest have gone for the PC parts of your question, I'll go with your monitors. But first I have to ask, which monitor do you mean with ASUS 23" Widescreen? Because ASUS has a lot of 23" monitors.

Regarding the Dell 2913WM, the 21:9 UltraWide monitor, it's a good monitor but it has equally good and cheaper alternatives from LG like the 29EA93 or the newer 29UB65 or ASUS' PB298Q (the best of the bunch for gaming). Just remember that not all the games work with that aspect ratio, going with a 16:9 pic and black bars on either side.