If you are an OnBuy customer and have forgotten your password you can reset it here.
It's worth double-checking that you are using the correct e-mail address.
The link will expire in 30 minutes, so if you've not used it in this timeframe, you'll need to generate a new one.
If you have not received your validation e-mail, firstly, please check that you have spelt your e-mail correctly.
It's also worth checking your junk mail and that donotreply@onbuy.com is on your Safe Send list.