I used msconfig to delete a couple non-essential programs from the startup. I've done this many times before and never had problems with it. However, the other day I tried it and when I rebooted my computer, almost nothing worked. Flash drives wouldn't recognize, the sound card in device manager was supposedly working properly, but if i tried to play anything it would tell me there was no sound card installed. The system slowed to a crawl, my virus scan, firewall, and pgp wouldn't start. I repaired the installation off of the original windows cd, and it fixed the sound problem, but then my network wouldn't show up, and device manager was a total blank. I happened to go into services.msc and there I found that every single thing was disabled. How on earth does something like that happen, and how can i prevent it from happening. It cost me hours of work to try and fix, and if i would have gotten any more frustrated, i probably would have resorted to a clean install.

Grafitti,

You didn't mention what non-essential programs you deleted. Maybe you could tell us what they were?

And you didn't say what version of Windows are you using.

But regardless, since you fixed the problem, perhaps I can give you one piece of advice .. Don't delete entries in the msconfig unless you're positively sure they are truly non-essential; you can simply disable them, which will have the exact same effect AND you're covered in case something goes wrong. You'll easily log into Safe Mode, enable the disabled item, and get everything back to normal.

A) follow K's advice
B)turn on system restore so you can just restore to a previous point if you screw things up again
C)use linux

but yea, just don't screw with anything if you dont know what it is, and make sure to make small numbers of changes at a time. Then at least you'll know what causes the problem if it happens again.

But yea, telling us what you turned off could help someone pinpoint the problem

Well, I tend to use MSCONFIG to turn off non essential programs at windows start, but I normally leave out system files since selectively turning on and off these files tends to be a bit of a headache. However, turning off applications that auto-start on boot (and especially those that do not allow you to select optionsthat disallow auto-run at boot) does speed up boot times by quite a bit by clearing out stuff youonly use once in a while, and also programs that tend to run in the background and use up CPU and memory. Frees up a lot of RAM too, so all in all it's a pretty good thing - as long as you don't fiddle around with the system centric auto-run applications that get used really often.

It was happened to me before too, I changed what I did to the old ones.Even Internet Explorer didn't work.When I looked at msconfig, Isaw that windows didn't open except itself.So you better undo the changes and the other answers were good too.

Ok, I got mixed up. I didn't delete them, simply disabled them. I did try to re-enable them, but it didn't make any difference. BUT... these were the entries I disabled:
Ypager (Yahoo Messenger), NeroCheck, Acrotray, Qttask (Quicktime), and Ypops.
As far as I know they don't have any bearing on the system startup status, other than using memory. I don't see how they could be related to the windows services.

Alright, now I really don't know what's going on.

You're right, the applications you mentioned do not have any bearing on the startup status or any other status, really. Although, I don't know much about NeroCheck since I don't use Nero. But I remember I tried to disable its autostart on a friend's computer, and as far as I could, this wasn't possible from within the application itself. I didn't get to the point of disabling it from msconfig, though, so I don't know if there'd be any consequences to the system.

Well, sorry I couldn't be of more help, but I'm glad you got your system back anyway. :-)

next time you change something in that file you should back it up and save a copy of it. So if you screw up you can easily go back to it.