Vista Ultimate x64 is restarting on the hour every hour

[89camaro]

hi ive had vista ultimate x64 installed for a little over a month.
on the morning of the 27th of last month i woke up to the login screen or rather vista booting woke me up at like 6 am. i logged on set somtheing running and wnt back to sleep. i woke upo later that day to the login screen again. i check the system log in the event viewer and saw that it had restarted every hour since it had woken me up the first time. preceded to do a sys restore to the 26th and all was well again. it stopped restarting on the hour till today when i came home from work to find the login screen again. i logged back on and it restarted an hour later. so i did another sys restore to the date of the 31st and it is fine again. now when it had strted restarting i hadnt installed anything new. after i did a system restore i installed nod32 cause i had been lazy about it. i had also read a post somewhere that said you can force vista to not restart on a system failure. and i did so but it did nothing to stop it from restarting. aslo when it started to restart today the msot recent thing i had installed was adobe reader 8.0 and that was the restore point i chose.

baisically id just like to know what could be causing this. all of my drivers are vista 64 compatible. it is a fiarily new system.

specs are
intel core 2 duo 4300 @1.8 ghz
intel classic series mb dg33bu
geforece fx 5200 256 meg gfz(driver is installed by vista havent tried to reinstall with a nvidia driver yet)
on board lan 1gbit
realtek HD audio(onboard as well)
and a raid card(vista installed the driver for this by searching online for it)
the ram is ddr2 800 or 667(im not sure of the brand and type as i never saw teh packaging when i bought it i had the store test and install teh chip and ram to the baord before i recieved ito make sure it worked so i didnt have to pay any diagnostic fees if it didnt if i did it myself)

all the drivers are from intel and they say they are vista 64 comaptible.
all but the on board vid which i dont use andyway and is disabled in the device manager are comp[atible according to vista as it yells at me when i try to install that one.

if there is a way to log the problem id like to know how alls i can get outta vista is in the sytem events code 6008 wwhich is unexpected system shutdown.
i do know that in xp if the system crashes it pos up the error reporting and usually sends you to the information.(had this happen with a linksys lan card)

ummm i cant think of anything more to add to help out whoever trys to help me.
if you need more info please post i will respond.

i should note that i had no problems with vista x32 on 2 previous installs(also ultimate) and on a previous install of x64. this is a dell version i got from a friend that im using if that matters and it is fully updated.

oh and pls forgive my lack of commas and capitals. i hate using them.
thanks in advance