There's a difference between validate and activate.
Activation is required each time the PC is reformatted and Windows
is reinstalled or when you install the OS on a brand new PC.
Validation is needed when access any Microsoft's sites.
If it's the validation that you did not pass, I can't handle this.
You have to email Microsoft Singapore (note: not the one in US, the
Microsoft branch in Singapore) and notify them about fake copies of
Windows so they could do something to the shop.
If it's activation, please go to Start > All Programs >
Activate Windows. If you did not pass this as well, again, notify
Microsoft Singapore.
Show them screenshots AND your receipt as proof, or you might into
trouble with Microsoft.