During playing graphic-intensive games, computer sometimes jams by shutting down the screen and not responding even though bg-processes seem to go on. The weird part is, that resetting doesn't help but I have to first turn the power down so I can get it to work. What the hell does the message "Please be resetting your DRAM and CPU frequency" mean? I haven't done any tweakings so where exactly is the problem?
To tell you the truth I have no clue what that error message means. But the first thing that I would make sure of is that you have enough power from your PSU to power the card.
check to see if the time & date is correct because if not then the cmos battery is dying thereby might be causing that error. does the videocard have a fan & if so is it spinning ok?
Good suggestions given. It sounds like a heat issue which is why, as ffg7 recommends, check to see if your card's fan is spinning. Intense games are going to make demands on your card which will heat up real fast. If the fan is working, then check your PSU as Spenman91 suggests or see if your other fans are working. CMOS may be going as well.