Windows 7 - Windows 7 is unstable

Hello all!
So...My Windows 7 applications just crash.Not all of them,not all at once.Propably they won't be even the same apps!Sometimes,no crash will occur.I get the "The program stopped working" error,and that's it.After I reboot,I run the same program,and it just runs perfectly.However,something else crashes this time.I believe it has to do with my ram (because different programs crash at different times,and a reboot fixes the problem...for a bit!).I don't have any memory drains though (about 17% of the usable ram is used).
I have done memory diagnostics and nothing came up.I am using both Windows and Linux (Debian and Suse),and both Linux run without a hiccup!
Ok,I know,I have too much ram for nothing,but that doesn't mean it must not work right!
I have reinstalled Windows 7 x64 (Ultimate) 4 times the last 5 months,and the same thing happens.I used to have BSODs,but they seem to have stopped for some reason.I had Windows 7 x86 (Ultimate) installed before,and it ran perfectly.That's what also makes me believe it has to do with the ram(8gb could not be seen by Windows 7 x86).
Oh,and I have installed Windows 7 x64 (Ultimate) from the same disc on my macbook pro,and it runs like a charm.No crashes or whatsoever.
Is there any fix for this?Any configuration I have to do?Fresh installs and repair installs didn't solve the issue.
Thanks in advance!

1. It could be malware related, run a free scan of malwarebytes: Malwarebytes Anti-Malware - Reviews and free Malwarebytes Anti-Malware downloads at Download.com

2. Update your mainboard drivers: http://pixel01.cps.intel.com/support...sktop/DP965LT/

It could be one of the drivers that is giving you a hard time. Run the DPC Latency Checker and see whether you get any red bars. If yes, there is most likely a driver problem.

Thank you both for your replies!
@ yowanvista: I have already done multiple scans for malware(with different software,one of them being malware bytes) and I've found nothing.Plus,I got Nod 32,and you can't go wrong with nod :P
Now,about the drivers:I have already installed the chipset drivers,but I haven't installed the lan ones,because Intel states clearly that they are for Windows Vista (x86 and x64).Should I install them?Can they be compatible with Windows 7?
@ whs: I ran the dpc latency checker,and the bars are constantly pretty low and green,so propably drivers are not the cause of the problem.What's ironic though is that I have ran the dpc latency checker on my macbook in the past,and I was getting plenty of red bars,even if things were working tight (or actually seemed they were ).

Hello !!

Check what is the DEP Setting set to in your Computer usually that used to cause problem. Follow this link for more info Data Execution Prevention: frequently asked questions make sure your Turn it off. Check the Event Viewer for Errors and post them here.

- Captain

@ Capt.Jack Sparrow: Thanks for your reply! I've been playing a bit with Windows settings,and I think I have found something that works...I turned off Dep,crashes kept going on.I also checked my Event Viewer,I was getting exception errors 0xc0000005 on different programs with each reboot.As I said before,the problem has to do with the ram.I set the maximum memory at the boot options (through msconfig) to 4095 mbs and I have no problems so far(after 5 reboots!).The thing is...I have 8gbs of ram and Windows x64,so...ok it's a solution,but obviously not the best one(I am happy that it works fine,though.)!Is there anything else I could try?

Edit:As it seems,I am not the only one with this kind of problem,I've read about similar problems all over the internet,but I haven't found a solution yet.

System Expection code 0xc0000005 bascially refers to some Firewall / Antivirus is blocking some important services like svchost.exe so if you have any uninstall it and see if that makes any difference.

-Captain

I uninstalled Nod 32,and in this reboot I got no crashes!I am using Windows Firewall,so I doubt that would cause any trouble...I am going to do some more test reboots and see what happens!

Edit:This is the fourth reboot,and no crashes are observed.In the past,my system wouldn't last that long :P Nod 32 was the source of the problem all along!5 months now,nod has been crashing my pc!Thanks Captain,you saved my rig! One question though:Which antivirus should I use now?Anything that compares to the perfomance of nod 32 (plus good compatibility with Windows 7 x64)?

Your Most Welcome !! Glad that you got it working !! Reagrding the AV and Firewall check our sticky threads Security Basics - Windows 7 Forums and What's the Best Anti-virus?. But I like Microsoft Security Essentials

- Captain

Well,I got to check only on the antiviruses,as I already got a hardware firewall(I have disabled Windows Firewall now).I have already checked MSE,and well,I liked it! :P It's probably the most compatible with Windows,so I'll stick with it (plus it has a x64 version).