Blue screen Error

[SARYJAMIE]

I have a lap top DELL Inspiron 6400.. first, it started to show the blue screen when i open many browsers telling that there's a memory error.. I tried to change my RAM but i got the same problem... i had to restart my lap top again and again to work... but after a while, the windows just stop working before it log in to the Welcome screen...
I wanted to format it but i have to back up my files first, they are really important files... when i connect the Hard Disk to other computer it doesn't work at all... any help please?

 

[Arc]

Post it following the Blue Screen of Death (BSOD) Posting Instructions.

 

[gregrocker]

The steps here will show you everything that can be done for Troubleshooting Windows 7 Failure to Start
including how to rescue your files using a boot disk and if necessary run Dell Windows 7 PC Restore or get the superior Clean Reinstall - Factory OEM Windows 7.

Disk for repairs or reinstall is provided in Step 6.