Windows Vista Major Computer Problems! (Blue Screening, Wont Boot, Nothing Displayed)

Hi,

Ive got serious problems with my PC. Probably easiest if I run through the series of events (some might just be coincidental);

1. About a week ago my PC started randomly turning itself off and blue screened. Thought it was probably overheating so cleaned the inside of my PC with vacuum cleaner (was pretty dusty). Also did a system restore and ran various anti-virus/malware/spyware programs just to make sure. Stopped turning itself off, but still blue screeing occasionally.

2. Turned PC off overnight. When I turned it back on it said couldnt boot into Windows. Tried doing a startup repair - said cannot complete. Restarted then selected Start Windows Normally and amazingly booted fine.

3. Continued to blue screen about once or twice a day. Cant remember exact messages but something like "Process Has Locked Pages" and various others. I raised the voltage of RAM to 2.45v in BIOS as this fixed BSoD errors in the past.

4. Used my computer this morning, blue screened. Came up with cannot boot windows etc. Restarted selected start windows normally as before. This time said "Welcome to Windows ", "Preparing Desktop" then BSoD before even getting into Windows!

5. Booted in safe mode to try and back up files. Said user profile was not properly loaded and blue screened after about 5 mins.

6. Thought maybe it was RAM causing errors. So tried to do some tests so I removed two sticks and restarted.

7. Then oddly NOTHING is displayed on the monitor. Not even the POST screen! So put the two ram sticks back and checked connections. I also tried using another GFX card (7800GTX) and two different monitors, still nothing!​

So now I cant even format the HDD or do anything! What could it be? Motherboard? RAM? Or could my HDD be so messed up that all the display drivers are corrupt?

Some extra info; My computers about 2.5 years old and have never reformatted. Ive had problems in the past of booting taking forever which I solved it by using a program called SpinRite which repairs bad sectors. But its probably not in good shape.

Please Help!




[SIZE= "1"]-------------------------------------------------------------------------------------------
CPU: Intel Q6600 Quad Core
OS: Windows Vista Home Premium (updated)
MOBO: Asus P5N-E SLI
PSU: 550W
RAM: 4GB DDR2 667MHz Memory (4x1GB)
GPU: nVIDIA GeForce 8800GTS 512MB
SFX: Creative Sound Blaster X-Fi Fatal1ty FPS
HDD: 2x 500GB SATA Hard Drive with 16MB Buffer
LCD: Samsung T220 22" Widescreen
-------------------------------------------------------------------------------------------[/SIZE]

 

Just a quick update... I took two memory sticks out then reset the CMOS by taking the mobo battery out and waiting a few minutes. Then switched on and the display is back!

Do I have reset the CMOS everytime I change the memory configeration? Should I be able to use the two in any of the four slots (two are black and two are yellow)?

 

Ok I think we've found the culprit! Ran memory test with first two sticks - 'pass complete, no errors'. Then put second lot in and got 6912 errors in about 20 seconds of running! It doesnt give a gauge of how bad this is, but Im guessing I need new RAM?

My current RAM I dont think is anything special; Samsung 1GB DDR2 667MHZ RAM (code on it is; 1GB 2Rx8 PC2 - 5300U - 555 - 12 - E3). Though I probably wont be able to a replacement stick, so guess Im gonna have to buy completely new set of RAM?

Whats the best RAM that my motherboard (Asus P5N-E SLI) supports? DDR3?