The company is also offering an further £100 if they trade-in their old PC, meaning customers can save up to £250 off the cost of a PC.
PC World's Tottenham Court Road Store in London will be opening at midnight on 21st October for PC users eager to get their hands on Microsoft's new operating system Windows 7.
The store said it will give the first 200 customers through its door, the chance to purchase Windows 7 for half the usual price.
Cameron McMillan, manger of the PC World Tottenham Court Road storesaid: "This is well worth staying up late for. By opening the doors at midnight our customers will not only be the first in the country to get hold of this fantastic new operating system but will also be able to advantage of some amazing deals in-store".
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See also: Windows 7 already shipping in the UK