Murphdog

You won't see much difference if any at all. The pro has a little faster write and a better warranty. It is hard for me to justify the extra money for the pro version. Unless you are really stuck on speed specs the 840 should be fine. Enjoy the vacation.

I prefer Samsung SSD's but have used Intel drives without issue in large deployments of computers that bake in mobile computers mounted near the windshield of vehicles. If money is not an object and speed is important then my favorite is: http://www.newegg.com/Product/Product.aspx?Item=N82E16820147193 A little cheaper http://www.newegg.com/Product/Product.aspx?Item=N82E16820147189 I recommend these assuming you have SATA III on your mobo. Shop around as you can probably get a better price and no sales tax. Since you don't want to keep the other drive you can use mini xp on the Hirens cd to recover your old data. Optionally you can install the old disk as a secondary disk. Watch what you back up because I am still leaning towards a malware issue as oppressed to a hardware issue. It's a crapshoot Good luck.

Can you boot into safe mode via F8 key after BIOS splash screen? If so does it stay running? I have been getting a lot of machines lately for repair with rootkits. They are basically a Trojan that hides from most antivirus suites. If that is the case you may have a rootkit and you can try Tdsskiller in safe mode to find and to remove it. The safest thing to do is format the disk and reinstall the OS. I have removed all traces of spyware and viruses from a machine and caught the malware still calling home via firewall logs. Format is the safest bet. If it is not malware flaky RAM and bad drivers can cause the issue also. The Hirens disk has some good tools for testing. It can be a lot of things but these are some basics. Regarding your RAM issue have you confirmed the motherboard supports more than 16GB of RAM?