BSOD frequently occurred over the last 2 weeks

Hi, my laptop kept having BSOD over the last two weeks, and I have no idea what caused the problem. It happened every 4 to 5 days. Sometimes even though I was doing nothing with my laptop, it still got BSOD.

I don't know whether it is relevant, but I also found out that System Restore in my laptop does not work. I have turned it on but it never creates a restore point. I also tried to create restore points manually, but they can never be detected when I run System Restore.

Spec:
My laptop is Windows 7 Home Premium 64-bit OEM and I purchased it 1 year ago and never re-installed the OS.
Processor: Intel Core i3 M 380 @ 2.53GHz
Memory: 4GB

Three issues


1-Avast. Remove and replace with Microsoft Security Essentials.

Avast can be a contributing cause of BSOD'S . Please remove and replace with Microsoft Security Essentials AT LEAST TO TEST


http://files.avast.com/files/eng/aswclear5.exe

http://www.microsoft.com/security_essentials/


2-Sptd.sys

Please remove any CD visualization programs such as Daemon Tools and Alcohol 120%.

They use a driver, found in your dmp, called sptd.sys, that is notorious for causing BSODs.

Use this SPTD uninstaller DuplexSecure - Downloads DuplexSecure - FAQ

when you're done you can use this Freeware:

MagicISO Virtual CD/DVD-ROM (MagicDisc) in its place

Using MagicISO to create ISO image files



3-Iastor.sys Re-install newest driver available.