Sellotape, maybe.
Nothing works like a dab of "Goop" silicone cement.
Static cling needs water with a drop of dish soap
One can buy Christmas window decorations online from websites like Ebay or from many retailers such as Walmart. One can also make Christmas window decorations by themselves, there are many articles online with instructions for homemade decoration.
The window may keep falling down and not staying up due to a faulty window regulator or a worn-out window track. These components can wear out over time, causing the window to not stay in the desired position.
The Peanuts Lighted Window Decorations do not come with replacement bulbs, but they use standard mini-bulbs, which are readily available locally.
Halloween window decorations can be purchased at most party stores, but can also be bought at big name stores such as Target or Walmart, and sometimes even local gas stations.
It does not say how it will mount.
I think it might be harder to find Christmas decorations during this time of year. When the holiday gets closer, you can find window decorations in stores like, Walmart, Kmart, and Target. Drug stores, like Rite Aid, also often carry them.
Your window may not stay up due to a faulty window regulator, worn-out window tracks, or a broken window balance. These components help support and hold the window in place, so if they are damaged or worn, the window may not stay up properly.
You can find unique ideas for Christmas window decorations at http://www.bhg.com/christmas/decorating/christmas-window-decorating-ideas. You can also find windows displays at http://shop.christmascentral.com/Xmas%20Lawn%20n%20Window%20Decor/Window_Decorations/ and http://www.christmascentral.com/content/pages/christmas-window-displays
Both of these household decorations are effective at keeping out light but this of course depends on the material and quality of the blinds or shades. Wooden blinds that rotate are very effective at keeping out light but so are blackout shades.
If one is wanting Christmas decorations for a window one can make decorations or purchase them. Some great ideas for making window decorations for Christmas can be found on the Better Homes and Gardens site. If one wishes to purchase these decorations there is a wide selection available all year round on sites such as Amazon and eBay.
there's a rumour that people use pumpkins as decorations to keep vampires away from houses during Halloween
The window may not stay up due to a faulty window regulator or a broken window mechanism. It could also be caused by worn-out window seals or a misaligned window track. These issues prevent the window from staying in the raised position.