a compaq presario cq60 was given to me a couple months ago; nothing fancy. its had some hiccups, but welcome to vista, right?

what seems to be a recurring theme with it, however, is freezing when i close a program. generally the only one i end via process is firefox when it starts running 300 or more mb ram. for some reason, it causes the whole system to lock up for several minutes. music/video hangs and loops whatever syllable it last played. even the mouse freezes. sometimes i get tired of waiting and do a hard reboot.

this happens with other programs, too - itunes, msn/yahoo messengers, etc. the most recent occurrence was with firefox. i manually closed each open window without problem. the Downloads window was last and running at 250mb ram. when i closed it, the computer locked up for 6 minutes.

is there something obvious i should be seeing? perhaps if i knew more about heaps and threads, id be able to see the issue before making the mistake of closing the wrong window.

its intermittent, but still fairly common.

any tips?