I'm sorry about the issue. Yes, you can. However, Microsoft and local stores do not sell Windows 7 any more; you would have to buy a windows 7 disk / license online like at eBay website. I don't recommend to install Windows 7 because it costs, and you will not get warranty support from Toshiba, and it takes time and it's complicated to do this.
I have a better and fast solution. I can make windows 8 look like windows 7 and easy to use like windows 7.
Can we do a remote support session, so I can troubleshoot the issue directly on your computer together with you?
Please reply at the box below. Thank you.