I'm in the UK and I have never come across this online store before.
That doesn't mean to say they are not genuine, but they are very meagre with their information. Their "Contact us" only gives an online email option, or an 0800 telephone number. Neither helps identify where they are, and with 0800 numbers, although free to call from a landline, they cost 40p per minute from a mobile. That's not unusual of course, but where is their history, their base, their references, and so on?
About that Microsoft Partnership. The logo is not clickable. That may be by design, I don't know, but I do know that scam sites will often just pull such 'certificate' logo images off the internet.
I went to the UK site for Microsoft Partnership, https://partner.microsoft.com/UK/Partner , but had difficulty finding any mention of TargetIT or T@rgetIT. That's not conclusive I must admit, because I found the site difficult to navigate to find any listing of existing partners.
I would say this. Their prices for Windows 7 Home Premium appear perfectly normal. Amazon.co.uk compares favourably.
But all in all, I would prefer to do business with those web sites and online stores that are recognised and established.
Mark