Gnome freezing/ screensaver locking it

[BWA]

Hey all, im relatively new to mint and am having a bit of an issue with my gui crashing.

im on the latest version of mint 12 (downloaded some updates last night), and was using my laptop today when suddenly the desktop stopped responding, in that i could still move the mouse around, banshee was still playing etc, but none of the menus would open when i clicked them, the only thing i could do was switch between workspaces but they werent working properly either.
if i right click on the desktop i get the menu from whatever program window was on top prior to this happening. im not really used to gnome, ive only used xfce before so am still getting used to it.

ive restarted like 5-6 times and this keeps happening

anyway my initial thought was that there was a bug in the update, but now im also thinking it might be the screensaver not working properly and disabling the desktop as it trys to run.

the computer im using is an old hp pavilion dv4000 (intel centrino processor i think). if anyone else has had a similar issue and can point me in the right direction for a solution i would be really grateful

sorry if this is the wrong section to post in, im new to these forums and theres a lot of sections

[BWA]

ok i tryed to turn off the screensaver to find that mint 12 doesnt even come with one, so im guessing its an issue with the computer dimming the screen and going into power saving mode or whatever its called.
it used to dim the screen after a few minutes and then youd need to enter the password to wake it up but now the desktop just becomes non functional instead

[BWA]

ok ive been playing around with this a bit to try and fix it (cos the computer is basically unusable right now) and the menus still seem to work only the actual menus dont show - i managed to lock the computer by clicking on the area of the desktop where the menu in the top right usually appears.

this issue seems to kick in when the computer has been unattended for like 5 mins

[BWA]

so i guess i didnt explain the problem clearly enough to get an answer or its a problem which is exclusive to my crappy laptop.

after using the computer for a bit, the dropdowns for the top bar (for volume, user, wireless connection etc) wont appear when i click them. the box outline over the icons still appears when i hover over them, but the actual menu box and contents dont show up. As well as this, clicking on any open programs on the bottom bar also does nothing. the fancy window switcher in the top left stops working as well-when clicking the button, nothing happens

the last time this happened i did ctrl alt t to bring up a terminal so i could reboot (because the usual shutdown/restart option under the username becomes unselectable due to this issue) but instead it kept opening new terminals over and over til the screen started going nuts with angled blocks of colour like when a graphics card dies because i guess it couldnt handle opening like 50 instances of terminal in a row after the equivalent of fork bombing itself

restarted using the power button to turn off and back on, and things are back to normal. its weird cos the menus only seem to stop working when im using programs that run windowed in the desktop (firefox, banshee, and libreoffice). when ive been watching tv shows on it fullscreened the menu/desktop problem doesnt seem to occur.

i would also like to state again that this issue did not happen until the last week or so, but now it means i have to restart like every 20 minutes when im not watching a fullscreen video, just to be able to use the desktop properly

so i guess my next question is how do i install another wm and set up mint to use that instead of gnome? was gonna go with xfce cos its what ive used before, plus this is a pretty old laptop, i wonder if gnome 3 is just too hectic for it.
ive not deviated from the default mint setup much aside from installing libreoffice, setting up a conky and a couple of other things. no serious tweaks or anything like that. would i be better off just reinstalling from scratch, cos ive been liking mint so far but id be tempted to go back to crunchbang if i cant get this sorted

ive managed to get this post typed out without losing the menus yet, but it really is making this computer totally unusable. ive also tryed to explain the problem more coherently but it is nearly 2am. maybe ill make a video showing the problem next time it happens, if that would be more help

[BWA]

there was an upstart update last night and things seem to be running better now, im hoping that a bad build previously was the problem here

[kcpoole]

I have seen this myself on 2 differnet HP laptops with a new install of Mint/
the machine effectively freezes after a while and only a Power off will fix it. Switched to Mate Desktop and does not happen at all.