Can't boot all the way with 4 gb.

I need some help, good SevenForums users. :)

I have a Dell E521 here at work that has had 2gb of RAM. I have Windows 7 64bit installed and just upgraded this morning to 4gb. The computer won't boot past the "Starting Windows" screen, where the fire flies swarm in. It will pause for about one minute there, then they'll start moving again and finally form the Microsoft Flag, or Banner, or whatever you want to call it. Then that's as far as it gets. It will just sit there, flashing the MS Flag and say "Starting Windows". I let it sit there for about 10 minutes so I'm pretty sure it isn't going anywhere.

If I back off and put just 2gb and 3gb (I tried both) of the new RAM in, it works great. So it has something to do with the 4gb barrier, which shouldn't exist because I'm using 64bit anyway. So let's just say it has something to do with 4gb being used.

3gb works great. If I have to I can use 3gb, but that defeats the purpose of having 64bit, and having 4gb that I just bought.

I have a feeling I could reinstall Windows 7 with 4gb in it originally and it would work. I'd prefer not to do that if possible, however I'm going to begin making sure my backups are in order just in case. If I don't get it figured out by 2:00 or so this afternoon I'll need to just go ahead and reinstall (assuming it will work if I go that route, I'm not 100% sure).

If anyone could provide suggestions here that would be great.

One more thing, my BIOS does recognize the full 4gb without any problem. I also am using the latest BIOS, I'm pretty sure (I looked on Dell's site). Also I checked the ACPI or whatever settings, and I don't have any version options, such as 1.0, 2.0, 3.0 etc to choose from. I read somewhere that could cause this sort of thing but alas I don't have those options.

Thanks in advance for any help.

99% sure the RAM is fine. They are identical sticks as well. All 4 are Crucial memory, same speeds and all that good stuff that they are supposed to be. Same speeds that were in my PC before.

As I said, all works great until the 4gb level is reached. 3gb works fine, 2gb works fine, etc.

OK, I'll humor you guys. Maybe you'll be the 1% that's right. :)

Link a good memtester, as I don't have one on here. What do you recommend?

Also, just to let you know, I have swapped out all the sticks so that all 4 have been in the PC in varying slots. For example, I had 3 in my PC at all times, but rotated all the sticks to different points, etc. The PC has worked fine so far, as long as there's only 3gb in it.

This is a commonly occurring problem. Sometimes, when it presents during install, the solution is to remove RAM, finish install, add the RAM back.

Another common solution, post install, is to boost either NB or MEM voltage. You have a Dell (condolences) so you cannot adjust voltages.

If you have the option to disable Legacy USB support, do so. If you have the option to disbale any onboard devices, do so.

Of course, you may be among the 1% who cannot run Win7x64 on a Dell.

Thanks for the replies. I found Memtest86 v 2.11 and am running that. So far it is 75% complete with no errors found and has been running for 1hr 20min.

@Antman - I'll try disabling some on board stuff, though I don't know how that will help. Could you explain how that might help here? I can't disable my onboard video because that's all I'm using for video. I can back off the legacy devices, that is if my mouse/keyboard that are USB will still work when I do that. I seem to remember enabling those options because of that reason in the past. Also the problem is that I can't run Win 7 x64, it's that I just can't seem to use 4gb with it. The OS runs great if I use 3g or less.

I could be wrong but it really seems like there is some type of problem with the jump to 4gb+, just because the OS wasn't installed with 4gb in it already. I imagine I'll end up reloading the system, though I really hate to do that since I basically just got everything on there and activated recently.

Thanks for the support so far guys, we'll get it figured out somehow!

Just an update. The Memtest program finished. 0 errors, so the memory is ok.