Where are you situated? US UK? Is there no way that I can convince you of how easy it is to put together a computer? Perhaps you have a friend that is more tech oriented that could help? I will shut up if you really can't be swayed, it's just that I can't stress the satisfaction of putting together a computer. When you put it together, that's when you want to have a glass panel to show off your PC's guts.
3 years ago, I would have said that cyberpower or ibuypower would be good but my opinion has dropped of them. Shoddily put together PCs with crap fans, I don't know and there customer service is crappy also.
If I were to get something pre-built right now I would probably go with an Asus or maybe Lenovo Desktop with the knowledge that my next upgrade will be a PSU and Graphics Card. These companies usually use an ATX PSU and have room for a full size graphics card.
Asus $659
http://www.walmart.com/ip/ASUS-CM1855-US006S-Desktop-PC-with-AMD-FX-8300-Processor-8GB-Memory-1TB-Hard-Drive-and-Windows-8-64-Bit-Monitor-Not-Included/27679909
Lenovo $679
http://www.bestbuy.com/site/lenovo-ideacentre-desktop-8gb-memory-1tb-hard-drive/8998157.p?id=1218968344463&skuId=8998157#tab=specifications
Acer LED Monitor $129
http://www.bestbuy.com/site/23-ips-led-hd-monitor/8869041.p?id=1218922148061&skuId=8869041&st=categoryid$pcmcat200900050014&cp=1&lp=2
EDIT: Just found this and must say that for that price and those guts, not bad. HD 7750 will get you through to next upgrade
IBUYPOWER $649
http://www.amazon.com/dp/B00EZ7NI5S/ref=asc_df_B00EZ7NI5S2865907?smid=ATVPDKIKX0DER&tag=nextagus0055894-20&linkCode=asn&creative=395093&creativeASIN=B00EZ7NI5S
AMD FX-Series Eight-Core FX-8320 Processor 3.5 GHz
8 GB DDR3 RAM; DVDRW Drive
1 TB 7200 rpm Hard Drive
Radeon HD7750 1GB Graphics
Windows 8.1