My new PC

Just over a month ago I bought a new PC windows 8.1, 12 GB RAM 2Gb graphics are the basic configurations of the PC.
After 4 days it just refused to start up so after 4 hours I phoned their support number and was told to turn the PC off by the power button then turn it back on still the same I told them, I had already tried it twice before calling them, they told me to call the other number to send it back for repair, I nearly told them it wasn't fit for purpose and I wanted NEW but decided it may be an update glitch and they will install a patch to stop it happening. They did this and replaced the graphics card as well, one of the nodules for the D-SUB connection was missing.
A week later it returned and the first thing I did was turn off automatic updates, all has gone well until I downloaded itunes to stream a pre-release of ROCK OR BUST the latest AC/DC new album. then the machine refused to shut down.
I tried a few things even a download to stop fast start-up but that failed but the actual solution was a very simple one just uninstall itunes  the machine is 64bit so I had installed the 64bit version of itunes.
First I uninstalled all the junk to do with itunes using revo uninstaller then as itunes didn't show I searched for it then uninstalled it then shut down the PC success the PC was now working as it should again.

Sometimes the simple solution is the best answer, in the time I have had this PC it has caused more problems than my last one, windows 7 home, did in nearly 6 years, this PC is no faster than the old one that was a 2.6 Athlon quad core with 1Gb graphics and 4 Gb RAM. I may send it back to the manufacturer for repair and have more RAM installed.

EDIT

I found out why my PC wouldn't shut down properly it's my  USB3 2 Terabyte external hard drive it stops the PC from shutting down since I disconnected it I haven't had the machine not shut down but the 500Gb USB2 works perfectly. I just started fast start up to see if the machine shuts down if it does then I effectively have 2 USB3 ports that are FUBAR.

NEW PC

Well my old PC stopped working, so I went out and bought a new one, only after 4 days the new one stopped working so it went back. They returned it to me on the 20/10/14 and they reminded me of some free software/app I could download in an email. I decided to look at them and a movie making program took my fancy. I put in the details and downloaded the app. I thought it had fucked up the PC as it said 100% done and kept spinning, eventually rebooting and letting me log in, on checking out the app it transpires it is only a maximum 30 day trial and they expect £60 to get a code to use it after 30 days, basically it's a con to entice you into buying that PC. That wasn't the only brand offering a free app some other brands did as well. £600 for a PC and they expect you to download an app then fork out £60 to use it after 30 days.

Currys/PCWorld are using underhand tactics to entice people to buy certain products by saying they will get something FREE, not a fucking free trial, that is just deceitful. If they had said receive a FREE TRIAL of selected software that would have been different.

I feel like putting the software onto a blank disc and stuffing it down the throat of the UK CEO of Currys/PCWorld, if you are ever enticed by a freebie like this I would always email and ask in future is it a FREE TRIAL of the software or the full working version, recording the conversation then if it shows up as a free trial you can then put in a claim against the store, if they say it is the full working version without any limitations, but turns out to be a FREE TRIAL of the full version.