There are many differences between router and modem besides their name
Modem-used for dialup connections where data that arrives as analog signals along the tp line are converted to binary signals for use in the pc
Router-used in adsl connections where data is ALREADY IN BINARY coz its sent...
Its good to have 2AVS on a pc, if one misses malfunctions, u have backup! :D but never leave both of them active, lik what blacknwhite said, itd slow the system and cause conflicts, leave one of them active and disable the other
Its overheating, the ram is loose or the psu (power supply unit) isn't powerful enuf, take out the ram and fix it back in. if that doesn't work, clean ur pc of dust completely(specially around the CPU,RAM and PSU) and also check whether all the fans are working. If u upgraded ur pc recently with...
I had the exactly same prob a few days ago, all i did was- take the whole thing apart, clean the dust, clean the ram contacts with an eraser (if u have an external graphix adapter clean that 2), put it back together and it worked fine!