I have also problem by not seeing pieces in Firefox. I did run TuneUp utilities program, and cleaning reagistry and some other stuff, now, i see empty board. What do i need to install, activex? Flash? I have both.
Pieces doesnt appear

If you use firefox, make sure you have javascript enabled.
If you use the NoScript plugin, turn it off. You can use that plugin to block single scripts rather than blocking all and allowing only some. If you prefer keeping it on, add chess.com and chesscomfiles.com to you white list.
If you experience this in live chess, wait for the new live app or make sure to completely empty your cache; you may consider to use ccleaner too. Check if you have the latest flash as well.

Thanx for quick answer, but i have java enabled, also latest flash, used ccleaner, but no solotuin. I know this is not my first time, and i did solve it but know i dont remember what was it.

Thanx for quick answer, but i have java enabled, also latest flash, used ccleaner, but no solotuin. I know this is not my first time, and i did solve it but know i dont remember what was it.
java or javascript? (It's not a trivial question, check it. You may have java enabled and javascript disabled). Try to change the board settings as well (i.e. the pieces style)
I have tried everything written in the faq/tutorial the hard refresh works but every time a new page loads I have to do a hard refresh to get the pieces on board...........I reached the part in tutorial where i should install a new browser, which for me wouldnt make the ideal solution...
If someone could help, I d be grateful..