You replaced the hard drive. What was on it, and/or what did you put on it?
This could very well be some hardware issue. I'd start booting into a Linux disc or stick (free to make) and see if that keeps working or freezes also.
The past couple of days I've had a few issues going on with my computer. The problems started with my 3d modeling program solidworks, it started running very slow and stopped responding, after that my computer froze. I let it sit for 5 minutes and nothing changed so I restarted the computer. This led to a blue screen that said "It looks like Windows didnt load correctly". This happened multiple times so I took it to geek squad and they said most likely a hard drive issue. Also had a friend who's in IT take a look and he said the same thing. So I replaced the hard drive, ando it was working okay and the computer was working okay for a few minutes and then froze again. I spent about 2 hours on the phone with Dell tech support and did all of their diagnostic tests and they determined that all of my hardware was working fine and that there might be a software issue. I noticed that some of the keys on my keyboard are only working intermittently and sometimes get mixed up (ie. I hit the N key and it puts a period.). Also my bios will not load. I tried, f2, f12, del, fn f2, fn f12, and the same on another keyboard. It seems like it's just ignoring the commands, and instead jumps right to the login screen. When I do login to the computer I can use it for about a minute before it freezes. I ran my computer in safe mode and it didn't seem to freeze(idk if that narrows the results). A friend also suggested my graphics card drivers may be out of date so I checked and they were indeed out of date but it also said (Nvidia genforce-something(32-bit)) I thought that was strange becsuse the computer is a 64bit system. So I installed the 64 but drivers and it didn't really change anything. Please help, I need my computer for work and school, and I'm pretty much screwed without it! Thanks!