Free-2-Play games (E.G. TF2 and Transformice) are not supposed to give any cards just for adding them to your library; instead they give 1 card for every 9$US you spend on them.

Non-F2P games give half (rounded up) the number of cards in the set. Trading/Selling/Using those free cards will not give you additional/replacement cards.

Double check your Badges page to make sure you have drops remaining. The yellow boxes in this image show where to look, just in case
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=503188239

Free-to-Play games do not give free drops just for adding them to your Library, you must spend 9$US for each drop. Non-F2P games give half (rounded up) the total number of cards in the set. Trading/Selling/Using those cards will not give you additional/replacement drops.

Very unlikely

Only site I can think of that even semi-regularly gives away games is Indie Gala[www.indiegala.com], although it's current offering does not have trading cards. You could use a site like Indie Game Bundles[indiegamebundles.com] to keep track of multiple other sites.

Try running it as Administrator

Once you have received your free drops from a game, that's it. There is no way to reset your free drops.

It can't be done because the number of free cards is controlled by Valve's servers and Valve has decided that you only get 1 batch of free cards.

Postat inițial de BrLc gizmo:

So, we need to buys game to get cards( or buy something in game). So we will losse money to get cards? If you don't sell your cards, is it better to make gems or the badge?

To get free cards from a non-F2P game you must own it. Generally this means you need to purchase it, but if you win it from a giveaway it still counts as ownership.

If you want cards from F2P you need to spend money, either through the in-game store at the rate of 1 card for every 9$US you spend on the in-game stuff, or off the Market for what ever's the going rate for the cards.

It's not impossible, but it's the first I've heard of it and I don't see a good reason to do so.

To what point? Running multiple games at the same time increases the time between drops. Best case, running 30 games at the same time takes the same amount of time of time as running 30 games one at a time, although some of the early testing showed that it increased the time beyond just running them sequentially.

This is of course assuming running more than 1 game at a time doesn't completely prevent drops as some people have reported.

If you really want to run multiple games to inflate your play time, just create a batch file and run that.